diff --git a/build/Android.gtest.mk b/build/Android.gtest.mk
index acaa0f8..66a16b6 100644
--- a/build/Android.gtest.mk
+++ b/build/Android.gtest.mk
@@ -59,6 +59,7 @@
 	runtime/reference_table_test.cc \
 	runtime/runtime_test.cc \
 	runtime/thread_pool_test.cc \
+	runtime/transaction_test.cc \
 	runtime/utils_test.cc \
 	runtime/verifier/method_verifier_test.cc \
 	runtime/verifier/reg_type_test.cc \
diff --git a/compiler/driver/compiler_driver.cc b/compiler/driver/compiler_driver.cc
index 5b22817..8678ad9 100644
--- a/compiler/driver/compiler_driver.cc
+++ b/compiler/driver/compiler_driver.cc
@@ -49,6 +49,7 @@
 #include "thread.h"
 #include "thread_pool.h"
 #include "trampolines/trampoline_compiler.h"
+#include "transaction.h"
 #include "verifier/method_verifier.h"
 #include "verifier/method_verifier-inl.h"
 
@@ -1795,425 +1796,6 @@
   context.ForAll(0, dex_file.NumClassDefs(), VerifyClass, thread_count_);
 }
 
-static const char* class_initializer_black_list[] = {
-  "Landroid/app/ActivityThread;",  // Calls regex.Pattern.compile -..-> regex.Pattern.compileImpl.
-  "Landroid/bluetooth/BluetoothAudioGateway;",  // Calls android.bluetooth.BluetoothAudioGateway.classInitNative().
-  "Landroid/bluetooth/HeadsetBase;",  // Calls android.bluetooth.HeadsetBase.classInitNative().
-  "Landroid/content/res/CompatibilityInfo;",  // Requires android.util.DisplayMetrics -..-> android.os.SystemProperties.native_get_int.
-  "Landroid/content/res/CompatibilityInfo$1;",  // Requires android.util.DisplayMetrics -..-> android.os.SystemProperties.native_get_int.
-  "Landroid/content/UriMatcher;",  // Calls regex.Pattern.compile -..-> regex.Pattern.compileImpl.
-  "Landroid/database/CursorWindow;",  // Requires android.util.DisplayMetrics -..-> android.os.SystemProperties.native_get_int.
-  "Landroid/database/sqlite/SQLiteConnection;",  // Calls regex.Pattern.compile -..-> regex.Pattern.compileImpl.
-  "Landroid/database/sqlite/SQLiteConnection$Operation;",  // Requires SimpleDateFormat -> java.util.Locale.
-  "Landroid/database/sqlite/SQLiteDatabaseConfiguration;",  // Calls regex.Pattern.compile -..-> regex.Pattern.compileImpl.
-  "Landroid/database/sqlite/SQLiteDebug;",  // Calls android.util.Log.isLoggable.
-  "Landroid/database/sqlite/SQLiteOpenHelper;",  // Calls Class.getSimpleName -> Class.isAnonymousClass -> Class.getDex.
-  "Landroid/database/sqlite/SQLiteQueryBuilder;",  // Calls regex.Pattern.compile -..-> regex.Pattern.compileImpl.
-  "Landroid/drm/DrmManagerClient;",  // Calls System.loadLibrary.
-  "Landroid/graphics/drawable/AnimatedRotateDrawable;",  // Sub-class of Drawable.
-  "Landroid/graphics/drawable/AnimationDrawable;",  // Sub-class of Drawable.
-  "Landroid/graphics/drawable/BitmapDrawable;",  // Sub-class of Drawable.
-  "Landroid/graphics/drawable/ClipDrawable;",  // Sub-class of Drawable.
-  "Landroid/graphics/drawable/ColorDrawable;",  // Sub-class of Drawable.
-  "Landroid/graphics/drawable/Drawable;",  // Requires android.graphics.Rect.
-  "Landroid/graphics/drawable/DrawableContainer;",  // Sub-class of Drawable.
-  "Landroid/graphics/drawable/GradientDrawable;",  // Sub-class of Drawable.
-  "Landroid/graphics/drawable/LayerDrawable;",  // Sub-class of Drawable.
-  "Landroid/graphics/drawable/NinePatchDrawable;",  // Sub-class of Drawable.
-  "Landroid/graphics/drawable/RotateDrawable;",  // Sub-class of Drawable.
-  "Landroid/graphics/drawable/ScaleDrawable;",  // Sub-class of Drawable.
-  "Landroid/graphics/drawable/ShapeDrawable;",  // Sub-class of Drawable.
-  "Landroid/graphics/drawable/StateListDrawable;",  // Sub-class of Drawable.
-  "Landroid/graphics/drawable/TransitionDrawable;",  // Sub-class of Drawable.
-  "Landroid/graphics/Matrix;",  // Calls android.graphics.Matrix.native_create.
-  "Landroid/graphics/Matrix$1;",  // Requires Matrix.
-  "Landroid/graphics/PixelFormat;",  // Calls android.graphics.PixelFormat.nativeClassInit().
-  "Landroid/graphics/Rect;",  // Calls regex.Pattern.compile -..-> regex.Pattern.compileImpl.
-  "Landroid/graphics/SurfaceTexture;",  // Calls android.graphics.SurfaceTexture.nativeClassInit().
-  "Landroid/graphics/Typeface;",  // Calls android.graphics.Typeface.nativeCreate.
-  "Landroid/inputmethodservice/ExtractEditText;",  // Requires android.widget.TextView.
-  "Landroid/media/AmrInputStream;",  // Calls OsConstants.initConstants.
-  "Landroid/media/CamcorderProfile;",  // Calls OsConstants.initConstants.
-  "Landroid/media/CameraProfile;",  // Calls System.loadLibrary.
-  "Landroid/media/DecoderCapabilities;",  // Calls System.loadLibrary.
-  "Landroid/media/EncoderCapabilities;",  // Calls OsConstants.initConstants.
-  "Landroid/media/ExifInterface;",  // Calls OsConstants.initConstants.
-  "Landroid/media/MediaCodec;",  // Calls OsConstants.initConstants.
-  "Landroid/media/MediaCodecList;",  // Calls OsConstants.initConstants.
-  "Landroid/media/MediaCrypto;",  // Calls OsConstants.initConstants.
-  "Landroid/media/MediaDrm;",  // Calls OsConstants.initConstants.
-  "Landroid/media/MediaExtractor;",  // Calls OsConstants.initConstants.
-  "Landroid/media/MediaFile;",  // Requires DecoderCapabilities.
-  "Landroid/media/MediaMetadataRetriever;",  // Calls OsConstants.initConstants.
-  "Landroid/media/MediaMuxer;",  // Calls OsConstants.initConstants.
-  "Landroid/media/MediaPlayer;",  // Calls System.loadLibrary.
-  "Landroid/media/MediaRecorder;",  // Calls System.loadLibrary.
-  "Landroid/media/MediaScanner;",  // Calls System.loadLibrary.
-  "Landroid/media/ResampleInputStream;",  // Calls OsConstants.initConstants.
-  "Landroid/media/SoundPool;",  // Calls OsConstants.initConstants.
-  "Landroid/media/videoeditor/MediaArtistNativeHelper;",  // Calls OsConstants.initConstants.
-  "Landroid/media/videoeditor/VideoEditorProfile;",  // Calls OsConstants.initConstants.
-  "Landroid/mtp/MtpDatabase;",  // Calls OsConstants.initConstants.
-  "Landroid/mtp/MtpDevice;",  // Calls OsConstants.initConstants.
-  "Landroid/mtp/MtpServer;",  // Calls OsConstants.initConstants.
-  "Landroid/net/NetworkInfo;",  // Calls java.util.EnumMap.<init> -> java.lang.Enum.getSharedConstants -> System.identityHashCode.
-  "Landroid/net/Proxy;",  // Calls regex.Pattern.compile -..-> regex.Pattern.compileImpl.
-  "Landroid/net/SSLCertificateSocketFactory;",  // Requires javax.net.ssl.HttpsURLConnection.
-  "Landroid/net/Uri$AbstractHierarchicalUri;",  // Requires Uri.
-  "Landroid/net/Uri$HierarchicalUri;",  // Requires Uri.
-  "Landroid/net/Uri$OpaqueUri;",  // Requires Uri.
-  "Landroid/net/Uri$StringUri;",  // Requires Uri.
-  "Landroid/net/Uri;",  // Calls Class.getSimpleName -> Class.isAnonymousClass -> Class.getDex.
-  "Landroid/net/WebAddress;",  // Calls regex.Pattern.compile -..-> regex.Pattern.compileImpl.
-  "Landroid/net/wifi/WifiNative;",  // Calls new LocalLog -> new Time -> TimeZone -> Pattern.compile.
-  "Landroid/nfc/NdefRecord;",  // Calls String.getBytes -> java.nio.charset.Charset.
-  "Landroid/opengl/EGL14;",  // Calls android.opengl.EGL14._nativeClassInit.
-  "Landroid/opengl/GLES10;",  // Calls android.opengl.GLES10._nativeClassInit.
-  "Landroid/opengl/GLES10Ext;",  // Calls android.opengl.GLES10Ext._nativeClassInit.
-  "Landroid/opengl/GLES11;",  // Requires GLES10.
-  "Landroid/opengl/GLES11Ext;",  // Calls android.opengl.GLES11Ext._nativeClassInit.
-  "Landroid/opengl/GLES20;",  // Calls android.opengl.GLES20._nativeClassInit.
-  "Landroid/opengl/GLUtils;",  // Calls android.opengl.GLUtils.nativeClassInit.
-  "Landroid/os/Build;",  // Calls -..-> android.os.SystemProperties.native_get.
-  "Landroid/os/Build$VERSION;",  // Requires Build.
-  "Landroid/os/Bundle;",  // Calls android.os.Parcel.obtain -..> Parcel.nativeCreate.
-  "Landroid/os/Debug;",  // Requires android.os.Environment.
-  "Landroid/os/Environment;",  // Calls System.getenv.
-  "Landroid/os/FileUtils;",  // Calls regex.Pattern.compile -..-> regex.Pattern.compileImpl.
-  "Landroid/os/StrictMode;",  // Calls android.util.Log.isLoggable.
-  "Landroid/os/StrictMode$VmPolicy;",  // Requires StrictMode.
-  "Landroid/os/Trace;",  // Calls android.os.Trace.nativeGetEnabledTags.
-  "Landroid/os/UEventObserver;",  // Calls Class.getSimpleName -> Class.isAnonymousClass -> Class.getDex.
-  "Landroid/provider/ContactsContract;",  // Calls OsConstants.initConstants.
-  "Landroid/provider/Settings$Global;",  // Calls OsConstants.initConstants.
-  "Landroid/provider/Settings$Secure;",  // Requires android.net.Uri.
-  "Landroid/provider/Settings$System;",  // Requires android.net.Uri.
-  "Landroid/renderscript/RenderScript;",  // Calls System.loadLibrary.
-  "Landroid/server/BluetoothService;",  // Calls android.server.BluetoothService.classInitNative.
-  "Landroid/server/BluetoothEventLoop;",  // Calls android.server.BluetoothEventLoop.classInitNative.
-  "Landroid/telephony/PhoneNumberUtils;",  // Calls regex.Pattern.compile -..-> regex.Pattern.compileImpl.
-  "Landroid/telephony/TelephonyManager;",  // Calls OsConstants.initConstants.
-  "Landroid/text/AutoText;",  // Requires android.util.DisplayMetrics -..-> android.os.SystemProperties.native_get_int.
-  "Landroid/text/Layout;",  // Calls com.android.internal.util.ArrayUtils.emptyArray -> System.identityHashCode.
-  "Landroid/text/BoringLayout;",  // Requires Layout.
-  "Landroid/text/DynamicLayout;",  // Requires Layout.
-  "Landroid/text/Html$HtmlParser;",  // Calls -..-> String.toLowerCase -> java.util.Locale.
-  "Landroid/text/StaticLayout;",  // Requires Layout.
-  "Landroid/text/TextUtils;",  // Requires android.util.DisplayMetrics.
-  "Landroid/util/DisplayMetrics;",  // Calls SystemProperties.native_get_int.
-  "Landroid/util/Patterns;",  // Calls regex.Pattern.compile -..-> regex.Pattern.compileImpl.
-  "Landroid/view/Choreographer;",  // Calls SystemProperties.native_get_boolean.
-  "Landroid/util/Patterns;",  // Calls regex.Pattern.compile -..-> regex.Pattern.compileImpl.
-  "Landroid/view/GLES20Canvas;",  // Calls GLES20Canvas.nIsAvailable().
-  "Landroid/view/GLES20RecordingCanvas;",  // Requires android.view.GLES20Canvas.
-  "Landroid/view/GestureDetector;",  // Calls android.view.GLES20Canvas.nIsAvailable.
-  "Landroid/view/HardwareRenderer$Gl20Renderer;",  // Requires SystemProperties.native_get.
-  "Landroid/view/HardwareRenderer$GlRenderer;",  // Requires SystemProperties.native_get.
-  "Landroid/view/InputEventConsistencyVerifier;",  // Requires android.os.Build.
-  "Landroid/view/Surface;",  // Requires SystemProperties.native_get.
-  "Landroid/view/SurfaceControl;",  // Calls OsConstants.initConstants.
-  "Landroid/view/animation/AlphaAnimation;",  // Requires Animation.
-  "Landroid/view/animation/Animation;",  // Calls SystemProperties.native_get_boolean.
-  "Landroid/view/animation/AnimationSet;",  // Calls OsConstants.initConstants.
-  "Landroid/view/textservice/SpellCheckerSubtype;",  // Calls Class.getDex().
-  "Landroid/webkit/JniUtil;",  // Calls System.loadLibrary.
-  "Landroid/webkit/PluginManager;",  // // Calls OsConstants.initConstants.
-  "Landroid/webkit/WebViewCore;",  // Calls System.loadLibrary.
-  "Landroid/webkit/WebViewFactory;",  // Calls -..-> android.os.SystemProperties.native_get.
-  "Landroid/webkit/WebViewFactory$Preloader;",  // Calls to Class.forName.
-  "Landroid/webkit/WebViewInputDispatcher;",  // Calls Calls regex.Pattern.compile -..-> regex.Pattern.compileImpl.
-  "Landroid/webkit/URLUtil;",  // Calls Calls regex.Pattern.compile -..-> regex.Pattern.compileImpl.
-  "Landroid/widget/AutoCompleteTextView;",  // Requires TextView.
-  "Landroid/widget/Button;",  // Requires TextView.
-  "Landroid/widget/CheckBox;",  // Requires TextView.
-  "Landroid/widget/CheckedTextView;",  // Requires TextView.
-  "Landroid/widget/CompoundButton;",  // Requires TextView.
-  "Landroid/widget/EditText;",  // Requires TextView.
-  "Landroid/widget/NumberPicker;",  // Requires java.util.Locale.
-  "Landroid/widget/ScrollBarDrawable;",  // Sub-class of Drawable.
-  "Landroid/widget/SearchView$SearchAutoComplete;",  // Requires TextView.
-  "Landroid/widget/Switch;",  // Requires TextView.
-  "Landroid/widget/TextView;",  // Calls Paint.<init> -> Paint.native_init.
-  "Lcom/android/i18n/phonenumbers/AsYouTypeFormatter;",  // Calls regex.Pattern.compile -..-> regex.Pattern.compileImpl.
-  "Lcom/android/i18n/phonenumbers/MetadataManager;",  // Calls OsConstants.initConstants.
-  "Lcom/android/i18n/phonenumbers/PhoneNumberMatcher;",  // Calls regex.Pattern.compile -..-> regex.Pattern.compileImpl.
-  "Lcom/android/i18n/phonenumbers/PhoneNumberUtil;",  // Requires java.util.logging.LogManager.
-  "Lcom/android/i18n/phonenumbers/geocoding/AreaCodeMap;",  // Calls OsConstants.initConstants.
-  "Lcom/android/i18n/phonenumbers/geocoding/PhoneNumberOfflineGeocoder;",  // Calls OsConstants.initConstants.
-  "Lcom/android/internal/os/SamplingProfilerIntegration;",  // Calls SystemProperties.native_get_int.
-  "Lcom/android/internal/policy/impl/PhoneWindow;",  // Calls android.os.Binder.init.
-  "Lcom/android/internal/view/menu/ActionMenuItemView;",  // Requires TextView.
-  "Lcom/android/internal/widget/DialogTitle;",  // Requires TextView.
-  "Lcom/android/org/bouncycastle/asn1/StreamUtil;",  // Calls Runtime.getRuntime().maxMemory().
-  "Lcom/android/org/bouncycastle/asn1/pkcs/MacData;",  // Calls native ... -> java.math.NativeBN.BN_new().
-  "Lcom/android/org/bouncycastle/asn1/pkcs/RSASSAPSSparams;",  // Calls native ... -> java.math.NativeBN.BN_new().
-  "Lcom/android/org/bouncycastle/asn1/cms/SignedData;",  // Calls native ... -> java.math.NativeBN.BN_new().
-  "Lcom/android/org/bouncycastle/asn1/x509/GeneralSubtree;",  // Calls native ... -> java.math.NativeBN.BN_new().
-  "Lcom/android/org/bouncycastle/asn1/x9/X9ECParameters;",  // Calls native ... -> java.math.NativeBN.BN_new().
-  "Lcom/android/org/bouncycastle/crypto/digests/OpenSSLDigest$MD5;",  // Requires com.android.org.conscrypt.NativeCrypto.
-  "Lcom/android/org/bouncycastle/crypto/digests/OpenSSLDigest$SHA1;",  // Requires com.android.org.conscrypt.NativeCrypto.
-  "Lcom/android/org/bouncycastle/crypto/digests/OpenSSLDigest$SHA256;",  // Requires com.android.org.conscrypt.NativeCrypto.
-  "Lcom/android/org/bouncycastle/crypto/digests/OpenSSLDigest$SHA384;",  // Requires com.android.org.conscrypt.NativeCrypto.
-  "Lcom/android/org/bouncycastle/crypto/digests/OpenSSLDigest$SHA512;",  // Requires com.android.org.conscrypt.NativeCrypto.
-  "Lcom/android/org/bouncycastle/crypto/engines/RSABlindedEngine;",  // Calls native ... -> java.math.NativeBN.BN_new().
-  "Lcom/android/org/bouncycastle/crypto/generators/DHKeyGeneratorHelper;",  // Calls native ... -> java.math.NativeBN.BN_new().
-  "Lcom/android/org/bouncycastle/crypto/generators/DHParametersGenerator;",  // Calls native ... -> java.math.NativeBN.BN_new().
-  "Lcom/android/org/bouncycastle/crypto/generators/DHParametersHelper;",  // Calls System.getenv -> OsConstants.initConstants.
-  "Lcom/android/org/bouncycastle/crypto/generators/DSAKeyPairGenerator;",  // Calls native ... -> java.math.NativeBN.BN_new().
-  "Lcom/android/org/bouncycastle/crypto/generators/DSAParametersGenerator;",  // Calls native ... -> java.math.NativeBN.BN_new().
-  "Lcom/android/org/bouncycastle/crypto/generators/RSAKeyPairGenerator;",  // Calls native ... -> java.math.NativeBN.BN_new().
-  "Lcom/android/org/bouncycastle/jcajce/provider/asymmetric/dh/KeyPairGeneratorSpi;",  // Calls OsConstants.initConstants.
-  "Lcom/android/org/bouncycastle/jcajce/provider/asymmetric/dsa/KeyPairGeneratorSpi;",  // Calls OsConstants.initConstants.
-  "Lcom/android/org/bouncycastle/jcajce/provider/asymmetric/ec/KeyPairGeneratorSpi$EC;",  // Calls OsConstants.initConstants.
-  "Lcom/android/org/bouncycastle/jcajce/provider/asymmetric/ec/KeyPairGeneratorSpi$ECDH;",  // Calls OsConstants.initConstants.
-  "Lcom/android/org/bouncycastle/jcajce/provider/asymmetric/ec/KeyPairGeneratorSpi$ECDHC;",  // Calls OsConstants.initConstants.
-  "Lcom/android/org/bouncycastle/jcajce/provider/asymmetric/ec/KeyPairGeneratorSpi$ECDSA;",  // Calls OsConstants.initConstants.
-  "Lcom/android/org/bouncycastle/jcajce/provider/asymmetric/ec/KeyPairGeneratorSpi$ECMQV;",  // Calls OsConstants.initConstants.
-  "Lcom/android/org/bouncycastle/jcajce/provider/asymmetric/ec/KeyPairGeneratorSpi;",  // Calls OsConstants.initConstants.
-  "Lcom/android/org/bouncycastle/jcajce/provider/asymmetric/rsa/BCRSAPrivateCrtKey;",  // Calls native ... -> java.math.NativeBN.BN_new().
-  "Lcom/android/org/bouncycastle/jcajce/provider/asymmetric/rsa/BCRSAPrivateKey;",  // Calls native ... -> java.math.NativeBN.BN_new().
-  "Lcom/android/org/bouncycastle/jcajce/provider/asymmetric/rsa/KeyPairGeneratorSpi;",  // Calls OsConstants.initConstants.
-  "Lcom/android/org/bouncycastle/jcajce/provider/keystore/pkcs12/PKCS12KeyStoreSpi$BCPKCS12KeyStore;",  // Calls Thread.currentThread.
-  "Lcom/android/org/bouncycastle/jcajce/provider/keystore/pkcs12/PKCS12KeyStoreSpi;",  // Calls Thread.currentThread.
-  "Lcom/android/org/bouncycastle/jce/PKCS10CertificationRequest;",  // Calls native ... -> java.math.NativeBN.BN_new().
-  "Lcom/android/org/bouncycastle/jce/provider/CertBlacklist;",  // Calls System.getenv -> OsConstants.initConstants.
-  "Lcom/android/org/bouncycastle/jce/provider/JCERSAPrivateCrtKey;",  // Calls native ... -> java.math.NativeBN.BN_new().
-  "Lcom/android/org/bouncycastle/jce/provider/JCERSAPrivateKey;",  // Calls native ... -> java.math.NativeBN.BN_new().
-  "Lcom/android/org/bouncycastle/jce/provider/PKIXCertPathValidatorSpi;",  // Calls System.getenv -> OsConstants.initConstants.
-  "Lcom/android/org/bouncycastle/math/ec/ECConstants;",  // Calls native ... -> java.math.NativeBN.BN_new().
-  "Lcom/android/org/bouncycastle/math/ec/Tnaf;",  // Calls native ... -> java.math.NativeBN.BN_new().
-  "Lcom/android/org/bouncycastle/util/BigIntegers;",  // Calls native ... -> java.math.NativeBN.BN_new().
-  "Lcom/android/org/bouncycastle/x509/X509Util;",  // Calls native ... -> java.math.NativeBN.BN_new().
-  "Lcom/android/org/conscrypt/CipherSuite;",  // Calls OsConstants.initConstants.
-  "Lcom/android/org/conscrypt/FileClientSessionCache$CacheFile;",  // Calls OsConstants.initConstants.
-  "Lcom/android/org/conscrypt/HandshakeIODataStream;",  // Calls OsConstants.initConstants.
-  "Lcom/android/org/conscrypt/Logger;",  // Calls OsConstants.initConstants.
-  "Lcom/android/org/conscrypt/NativeCrypto;",  // Calls native NativeCrypto.clinit().
-  "Lcom/android/org/conscrypt/OpenSSLECKeyPairGenerator;",  // Calls OsConstants.initConstants.
-  "Lcom/android/org/conscrypt/OpenSSLEngine;",  // Requires com.android.org.conscrypt.NativeCrypto.
-  "Lcom/android/org/conscrypt/OpenSSLMac$HmacMD5;",  // Calls native NativeCrypto.clinit().
-  "Lcom/android/org/conscrypt/OpenSSLMac$HmacSHA1;",  // Calls native NativeCrypto.clinit().
-  "Lcom/android/org/conscrypt/OpenSSLMac$HmacSHA256;",  // Calls native NativeCrypto.clinit().
-  "Lcom/android/org/conscrypt/OpenSSLMac$HmacSHA384;",  // Calls native NativeCrypto.clinit().
-  "Lcom/android/org/conscrypt/OpenSSLMac$HmacSHA512;",  // Calls native NativeCrypto.clinit().
-  "Lcom/android/org/conscrypt/OpenSSLMessageDigestJDK$MD5;",  // Requires com.android.org.conscrypt.NativeCrypto.
-  "Lcom/android/org/conscrypt/OpenSSLMessageDigestJDK$SHA1;",  // Requires com.android.org.conscrypt.NativeCrypto.
-  "Lcom/android/org/conscrypt/OpenSSLMessageDigestJDK$SHA256;",  // Requires com.android.org.conscrypt.NativeCrypto.
-  "Lcom/android/org/conscrypt/OpenSSLMessageDigestJDK$SHA384;",  // Requires com.android.org.conscrypt.NativeCrypto.
-  "Lcom/android/org/conscrypt/OpenSSLMessageDigestJDK$SHA512;",  // Requires com.android.org.conscrypt.NativeCrypto.
-  "Lcom/android/org/conscrypt/OpenSSLX509CertPath;",  // Calls OsConstants.initConstants.
-  "Lcom/android/org/conscrypt/OpenSSLX509CertificateFactory;",  // Calls OsConstants.initConstants.
-  "Lcom/android/org/conscrypt/PRF;",  // Calls OsConstants.initConstants.
-  "Lcom/android/org/conscrypt/SSLSessionImpl;",  // Calls OsConstants.initConstants.
-  "Lcom/android/org/conscrypt/TrustedCertificateStore;",  // Calls System.getenv -> OsConstants.initConstants.
-  "Lcom/android/okhttp/ConnectionPool;",  // Calls OsConstants.initConstants.
-  "Lcom/android/okhttp/OkHttpClient;",  // Calls OsConstants.initConstants.
-  "Lcom/android/okhttp/internal/DiskLruCache;",  // Calls regex.Pattern.compile -..-> regex.Pattern.compileImpl.
-  "Lcom/android/okhttp/internal/Util;",  // Calls OsConstants.initConstants.
-  "Lcom/android/okhttp/internal/http/HttpsURLConnectionImpl;",  // Calls VMClassLoader.getBootClassPathSize.
-  "Lcom/android/okhttp/internal/spdy/SpdyConnection;",  // Calls OsConstants.initConstants.
-  "Lcom/android/okhttp/internal/spdy/SpdyReader;",  // Calls OsConstants.initConstants.
-  "Lcom/android/okhttp/internal/tls/OkHostnameVerifier;",  // Calls regex.Pattern.compile -..-> regex.Pattern.compileImpl.
-  "Lcom/google/android/gles_jni/EGLContextImpl;",  // Calls com.google.android.gles_jni.EGLImpl._nativeClassInit.
-  "Lcom/google/android/gles_jni/EGLImpl;",  // Calls com.google.android.gles_jni.EGLImpl._nativeClassInit.
-  "Lcom/google/android/gles_jni/GLImpl;",  // Calls com.google.android.gles_jni.GLImpl._nativeClassInit.
-  "Lgov/nist/core/GenericObject;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/core/Host;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/core/HostPort;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/core/NameValue;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/core/net/DefaultNetworkLayer;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/Utils;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/address/AddressImpl;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/address/Authority;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/address/GenericURI;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/address/NetObject;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/address/SipUri;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/address/TelephoneNumber;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/address/UserInfo;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/Accept;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/AcceptEncoding;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/AcceptLanguage;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/AddressParametersHeader;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/AlertInfoList;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/AllowEvents;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/AllowEventsList;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/AuthenticationInfo;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/Authorization;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/CSeq;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/CallIdentifier;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/Challenge;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/ContactList;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/ContentEncoding;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/ContentEncodingList;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/ContentLanguageList;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/ContentType;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/Credentials;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/ErrorInfoList;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/Expires;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/From;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/MimeVersion;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/NameMap;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/Priority;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/Protocol;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/ProxyAuthenticate;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/ProxyAuthenticateList;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/ProxyAuthorizationList;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/ProxyRequire;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/ProxyRequireList;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/RSeq;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/RecordRoute;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/ReferTo;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/RequestLine;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/Require;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/RetryAfter;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/SIPETag;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/SIPHeader;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/SIPHeaderNamesCache;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/StatusLine;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/SubscriptionState;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/TimeStamp;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/UserAgent;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/Unsupported;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/Warning;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/ViaList;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/extensions/Join;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/extensions/References;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/extensions/Replaces;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/ims/PAccessNetworkInfo;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/ims/PAssertedIdentity;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/ims/PAssertedIdentityList;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/ims/PAssociatedURI;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/ims/PCalledPartyID;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/ims/PChargingVector;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/ims/PPreferredIdentity;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/ims/PVisitedNetworkIDList;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/ims/PathList;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/ims/SecurityAgree;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/ims/SecurityClient;",  // Calls OsConstants.initConstants.
-  "Lgov/nist/javax/sip/header/ims/ServiceRoute;",  // Calls OsConstants.initConstants.
-  "Ljava/io/Console;",  // Has FileDescriptor(s).
-  "Ljava/io/File;",  // Calls to Random.<init> -> System.currentTimeMillis -> OsConstants.initConstants.
-  "Ljava/io/FileDescriptor;",  // Requires libcore.io.OsConstants.
-  "Ljava/io/ObjectInputStream;",  // Requires java.lang.ClassLoader$SystemClassLoader.
-  "Ljava/io/ObjectStreamClass;",  // Calls to Class.forName -> java.io.FileDescriptor.
-  "Ljava/io/ObjectStreamConstants;",  // Instance of non-image class SerializablePermission.
-  "Ljava/lang/ClassLoader$SystemClassLoader;",  // Calls System.getProperty -> OsConstants.initConstants.
-  "Ljava/lang/HexStringParser;",  // Calls regex.Pattern.compile -..-> regex.Pattern.compileImpl.
-  "Ljava/lang/ProcessManager;",  // Calls Thread.currentThread.
-  "Ljava/lang/Runtime;",  // Calls System.getProperty -> OsConstants.initConstants.
-  "Ljava/lang/System;",  // Calls OsConstants.initConstants.
-  "Ljava/math/BigDecimal;",  // Calls native ... -> java.math.NativeBN.BN_new().
-  "Ljava/math/BigInteger;",  // Calls native ... -> java.math.NativeBN.BN_new().
-  "Ljava/math/Primality;",  // Calls native ... -> java.math.NativeBN.BN_new().
-  "Ljava/math/Multiplication;",  // Calls native ... -> java.math.NativeBN.BN_new().
-  "Ljava/net/InetAddress;",  // Requires libcore.io.OsConstants.
-  "Ljava/net/Inet4Address;",  // Sub-class of InetAddress.
-  "Ljava/net/Inet6Address;",  // Sub-class of InetAddress.
-  "Ljava/net/InetUnixAddress;",  // Sub-class of InetAddress.
-  "Ljava/net/NetworkInterface;",  // Calls to Random.<init> -> System.currentTimeMillis -> OsConstants.initConstants.
-  "Ljava/net/StandardSocketOptions;",  // Call System.identityHashCode.
-  "Ljava/nio/charset/Charset;",  // Calls Charset.getDefaultCharset -> System.getProperty -> OsConstants.initConstants.
-  "Ljava/nio/charset/CharsetICU;",  // Sub-class of Charset.
-  "Ljava/nio/charset/Charsets;",  // Calls Charset.forName.
-  "Ljava/nio/charset/StandardCharsets;",  // Calls OsConstants.initConstants.
-  "Ljava/security/AlgorithmParameterGenerator;",  // Calls OsConstants.initConstants.
-  "Ljava/security/KeyPairGenerator$KeyPairGeneratorImpl;",  // Calls OsConstants.initConstants.
-  "Ljava/security/KeyPairGenerator;",  // Calls OsConstants.initConstants.
-  "Ljava/security/Security;",  // Tries to do disk IO for "security.properties".
-  "Ljava/security/spec/RSAKeyGenParameterSpec;",  // java.math.NativeBN.BN_new()
-  "Ljava/sql/Date;",  // Calls OsConstants.initConstants.
-  "Ljava/sql/DriverManager;",  // Calls OsConstants.initConstants.
-  "Ljava/sql/Time;",  // Calls OsConstants.initConstants.
-  "Ljava/sql/Timestamp;",  // Calls OsConstants.initConstants.
-  "Ljava/util/Date;",  // Calls Date.<init> -> System.currentTimeMillis -> OsConstants.initConstants.
-  "Ljava/util/ListResourceBundle;",  // Calls OsConstants.initConstants.
-  "Ljava/util/Locale;",  // Calls System.getProperty -> OsConstants.initConstants.
-  "Ljava/util/PropertyResourceBundle;",  // Calls OsConstants.initConstants.
-  "Ljava/util/ResourceBundle;",  // Calls OsConstants.initConstants.
-  "Ljava/util/ResourceBundle$MissingBundle;",  // Calls OsConstants.initConstants.
-  "Ljava/util/Scanner;",  // regex.Pattern.compileImpl.
-  "Ljava/util/SimpleTimeZone;",  // Sub-class of TimeZone.
-  "Ljava/util/TimeZone;",  // Calls regex.Pattern.compile -..-> regex.Pattern.compileImpl.
-  "Ljava/util/concurrent/ConcurrentHashMap;",  // Calls Runtime.getRuntime().availableProcessors().
-  "Ljava/util/concurrent/ConcurrentHashMap$Segment;",  // Calls Runtime.getRuntime().availableProcessors().
-  "Ljava/util/concurrent/ConcurrentSkipListMap;",  // Calls Random() -> OsConstants.initConstants.
-  "Ljava/util/concurrent/Exchanger;",  // Calls Runtime.getRuntime().availableProcessors().
-  "Ljava/util/concurrent/ForkJoinPool;",  // Makes a thread pool ..-> calls OsConstants.initConstants.
-  "Ljava/util/concurrent/LinkedTransferQueue;",  // Calls Runtime.getRuntime().availableProcessors().
-  "Ljava/util/concurrent/Phaser;",  // Calls Runtime.getRuntime().availableProcessors().
-  "Ljava/util/concurrent/ScheduledThreadPoolExecutor;",  // Calls AtomicLong.VMSupportsCS8()
-  "Ljava/util/concurrent/SynchronousQueue;",  // Calls Runtime.getRuntime().availableProcessors().
-  "Ljava/util/concurrent/atomic/AtomicLong;",  // Calls AtomicLong.VMSupportsCS8()
-  "Ljava/util/logging/LogManager;",  // Calls System.getProperty -> OsConstants.initConstants.
-  "Ljava/util/prefs/AbstractPreferences;",  // Calls OsConstants.initConstants.
-  "Ljava/util/prefs/FilePreferencesImpl;",  // Calls OsConstants.initConstants.
-  "Ljava/util/prefs/FilePreferencesFactoryImpl;",  // Calls OsConstants.initConstants.
-  "Ljava/util/prefs/Preferences;",  // Calls OsConstants.initConstants.
-  "Ljavax/crypto/KeyAgreement;",  // Calls OsConstants.initConstants.
-  "Ljavax/crypto/KeyGenerator;",  // Calls OsConstants.initConstants.
-  "Ljavax/security/cert/X509Certificate;",  // Calls VMClassLoader.getBootClassPathSize.
-  "Ljavax/security/cert/X509Certificate$1;",  // Calls VMClassLoader.getBootClassPathSize.
-  "Ljavax/microedition/khronos/egl/EGL10;",  // Requires EGLContext.
-  "Ljavax/microedition/khronos/egl/EGLContext;",  // Requires com.google.android.gles_jni.EGLImpl.
-  "Ljavax/xml/datatype/DatatypeConstants;",  // Calls OsConstants.initConstants.
-  "Ljavax/xml/datatype/FactoryFinder;",  // Calls OsConstants.initConstants.
-  "Ljavax/xml/namespace/QName;",  // Calls OsConstants.initConstants.
-  "Ljavax/xml/validation/SchemaFactoryFinder;",  // Calls OsConstants.initConstants.
-  "Ljavax/xml/xpath/XPathConstants;",  // Calls OsConstants.initConstants.
-  "Ljavax/xml/xpath/XPathFactoryFinder;",  // Calls OsConstants.initConstants.
-  "Llibcore/icu/LocaleData;",  // Requires java.util.Locale.
-  "Llibcore/icu/TimeZoneNames;",  // Requires java.util.TimeZone.
-  "Llibcore/io/IoUtils;",  // Calls Random.<init> -> System.currentTimeMillis -> FileDescriptor -> OsConstants.initConstants.
-  "Llibcore/io/OsConstants;",  // Platform specific.
-  "Llibcore/net/MimeUtils;",  // Calls libcore.net.MimeUtils.getContentTypesPropertiesStream -> System.getProperty.
-  "Llibcore/reflect/Types;",  // Calls OsConstants.initConstants.
-  "Llibcore/util/ZoneInfo;",  // Sub-class of TimeZone.
-  "Llibcore/util/ZoneInfoDB;",  // Calls System.getenv -> OsConstants.initConstants.
-  "Lorg/apache/commons/logging/LogFactory;",  // Calls System.getProperty.
-  "Lorg/apache/commons/logging/impl/LogFactoryImpl;",  // Calls OsConstants.initConstants.
-  "Lorg/apache/harmony/security/fortress/Services;",  // Calls ClassLoader.getSystemClassLoader -> System.getProperty.
-  "Lorg/apache/harmony/security/provider/cert/X509CertFactoryImpl;",  // Requires java.nio.charsets.Charsets.
-  "Lorg/apache/harmony/security/provider/crypto/RandomBitsSupplier;",  // Requires java.io.File.
-  "Lorg/apache/harmony/security/utils/AlgNameMapper;",  // Requires java.util.Locale.
-  "Lorg/apache/harmony/security/pkcs10/CertificationRequest;",  // Calls Thread.currentThread.
-  "Lorg/apache/harmony/security/pkcs10/CertificationRequestInfo;",  // Calls Thread.currentThread.
-  "Lorg/apache/harmony/security/pkcs7/AuthenticatedAttributes;",  // Calls Thread.currentThread.
-  "Lorg/apache/harmony/security/pkcs7/SignedData;",  // Calls Thread.currentThread.
-  "Lorg/apache/harmony/security/pkcs7/SignerInfo;",  // Calls Thread.currentThread.
-  "Lorg/apache/harmony/security/pkcs8/PrivateKeyInfo;",  // Calls Thread.currentThread.
-  "Lorg/apache/harmony/security/provider/crypto/SHA1PRNG_SecureRandomImpl;",  // Calls OsConstants.initConstants.
-  "Lorg/apache/harmony/security/x501/AttributeTypeAndValue;",  // Calls IntegralToString.convertInt -> Thread.currentThread.
-  "Lorg/apache/harmony/security/x501/DirectoryString;",  // Requires BigInteger.
-  "Lorg/apache/harmony/security/x501/Name;",  // Requires org.apache.harmony.security.x501.AttributeTypeAndValue.
-  "Lorg/apache/harmony/security/x509/AccessDescription;",  // Calls Thread.currentThread.
-  "Lorg/apache/harmony/security/x509/AuthorityKeyIdentifier;",  // Calls Thread.currentThread.
-  "Lorg/apache/harmony/security/x509/CRLDistributionPoints;",  // Calls Thread.currentThread.
-  "Lorg/apache/harmony/security/x509/Certificate;",  // Requires org.apache.harmony.security.x509.TBSCertificate.
-  "Lorg/apache/harmony/security/x509/CertificateIssuer;",  // Calls Thread.currentThread.
-  "Lorg/apache/harmony/security/x509/CertificateList;",  // Calls Thread.currentThread.
-  "Lorg/apache/harmony/security/x509/DistributionPoint;",  // Calls Thread.currentThread.
-  "Lorg/apache/harmony/security/x509/DistributionPointName;",  // Calls Thread.currentThread.
-  "Lorg/apache/harmony/security/x509/EDIPartyName;",  // Calls native ... -> java.math.NativeBN.BN_new().
-  "Lorg/apache/harmony/security/x509/GeneralName;",  // Requires org.apache.harmony.security.x501.Name.
-  "Lorg/apache/harmony/security/x509/GeneralNames;",  // Requires GeneralName.
-  "Lorg/apache/harmony/security/x509/GeneralSubtree;",  // Calls Thread.currentThread.
-  "Lorg/apache/harmony/security/x509/GeneralSubtrees;",  // Calls Thread.currentThread.
-  "Lorg/apache/harmony/security/x509/InfoAccessSyntax;",  // Calls Thread.currentThread.
-  "Lorg/apache/harmony/security/x509/IssuingDistributionPoint;",  // Calls Thread.currentThread.
-  "Lorg/apache/harmony/security/x509/NameConstraints;",  // Calls Thread.currentThread.
-  "Lorg/apache/harmony/security/x509/TBSCertList$RevokedCertificate;",  // Calls NativeBN.BN_new().
-  "Lorg/apache/harmony/security/x509/TBSCertList;",  // Calls Thread.currentThread.
-  "Lorg/apache/harmony/security/x509/TBSCertificate;",  // Requires org.apache.harmony.security.x501.Name.
-  "Lorg/apache/harmony/security/x509/Time;",  // Calls native ... -> java.math.NativeBN.BN_new().
-  "Lorg/apache/harmony/security/x509/Validity;",  // Requires x509.Time.
-  "Lorg/apache/harmony/security/x509/tsp/TSTInfo;",  // Calls Thread.currentThread.
-  "Lorg/apache/harmony/xml/ExpatParser;",  // Calls native ExpatParser.staticInitialize.
-  "Lorg/apache/harmony/xml/ExpatParser$EntityParser;",  // Calls ExpatParser.staticInitialize.
-  "Lorg/apache/http/conn/params/ConnRouteParams;",  // Requires java.util.Locale.
-  "Lorg/apache/http/conn/ssl/SSLSocketFactory;",  // Calls java.security.Security.getProperty.
-  "Lorg/apache/http/conn/util/InetAddressUtils;",  // Calls regex.Pattern.compile -..-> regex.Pattern.compileImpl.
-};
-
 static void InitializeClass(const ParallelCompilationManager* manager, size_t class_def_index)
     LOCKS_EXCLUDED(Locks::mutator_lock_) {
   ATRACE_CALL();
@@ -2251,33 +1833,49 @@
         manager->GetClassLinker()->EnsureInitialized(klass, false, true);
         if (!klass->IsInitialized()) {
           // We need to initialize static fields, we only do this for image classes that aren't
-          // black listed or marked with the $NoPreloadHolder.
+          // marked with the $NoPreloadHolder (which implies this should not be initialized early).
           bool can_init_static_fields = manager->GetCompiler()->IsImage() &&
-              manager->GetCompiler()->IsImageClass(descriptor);
+              manager->GetCompiler()->IsImageClass(descriptor) &&
+              !StringPiece(descriptor).ends_with("$NoPreloadHolder;");
           if (can_init_static_fields) {
-            // NoPreloadHolder inner class implies this should not be initialized early.
-            bool is_black_listed = StringPiece(descriptor).ends_with("$NoPreloadHolder;");
-            if (!is_black_listed) {
-              for (size_t i = 0; i < arraysize(class_initializer_black_list); ++i) {
-                if (strcmp(descriptor, class_initializer_black_list[i]) == 0) {
-                  is_black_listed = true;
-                  break;
-                }
+            VLOG(compiler) << "Initializing: " << descriptor;
+            if (strcmp("Ljava/lang/Void;", descriptor) == 0) {
+              // Hand initialize j.l.Void to avoid Dex file operations in un-started runtime.
+              ObjectLock<mirror::Class> lock(soa.Self(), &klass);
+              mirror::ObjectArray<mirror::ArtField>* fields = klass->GetSFields();
+              CHECK_EQ(fields->GetLength(), 1);
+              fields->Get(0)->SetObj<false>(klass.get(),
+                                                     manager->GetClassLinker()->FindPrimitiveClass('V'));
+              klass->SetStatus(mirror::Class::kStatusInitialized, soa.Self());
+            } else {
+              // TODO multithreading support. We should ensure the current compilation thread has
+              // exclusive access to the runtime and the transaction. To achieve this, we could use
+              // a ReaderWriterMutex but we're holding the mutator lock so we fail mutex sanity
+              // checks in Thread::AssertThreadSuspensionIsAllowable.
+              Runtime* const runtime = Runtime::Current();
+              Transaction transaction;
+
+              // Run the class initializer in transaction mode.
+              runtime->EnterTransactionMode(&transaction);
+              const mirror::Class::Status old_status = klass->GetStatus();
+              bool success = manager->GetClassLinker()->EnsureInitialized(klass, true, true);
+              // TODO we detach transaction from runtime to indicate we quit the transactional
+              // mode which prevents the GC from visiting objects modified during the transaction.
+              // Ensure GC is not run so don't access freed objects when aborting transaction.
+              const char* old_casue = soa.Self()->StartAssertNoThreadSuspension("Transaction end");
+              runtime->ExitTransactionMode();
+
+              if (!success) {
+                CHECK(soa.Self()->IsExceptionPending());
+                ThrowLocation throw_location;
+                mirror::Throwable* exception = soa.Self()->GetException(&throw_location);
+                VLOG(compiler) << "Initialization of " << descriptor << " aborted because of "
+                               << exception->Dump();
+                soa.Self()->ClearException();
+                transaction.Abort();
+                CHECK_EQ(old_status, klass->GetStatus()) << "Previous class status not restored";
               }
-            }
-            if (!is_black_listed) {
-              VLOG(compiler) << "Initializing: " << descriptor;
-              if (strcmp("Ljava/lang/Void;", descriptor) == 0) {
-                // Hand initialize j.l.Void to avoid Dex file operations in un-started runtime.
-                ObjectLock<mirror::Class> lock(soa.Self(), &klass);
-                mirror::ObjectArray<mirror::ArtField>* fields = klass->GetSFields();
-                CHECK_EQ(fields->GetLength(), 1);
-                fields->Get(0)->SetObj(klass.get(),
-                                       manager->GetClassLinker()->FindPrimitiveClass('V'));
-                klass->SetStatus(mirror::Class::kStatusInitialized, soa.Self());
-              } else {
-                manager->GetClassLinker()->EnsureInitialized(klass, true, true);
-              }
+              soa.Self()->EndAssertNoThreadSuspension(old_casue);
             }
           }
         }
@@ -2295,18 +1893,20 @@
 void CompilerDriver::InitializeClasses(jobject jni_class_loader, const DexFile& dex_file,
                                        ThreadPool& thread_pool, TimingLogger& timings) {
   timings.NewSplit("InitializeNoClinit");
-#ifndef NDEBUG
-  // Sanity check blacklist descriptors.
-  if (IsImage()) {
-    for (size_t i = 0; i < arraysize(class_initializer_black_list); ++i) {
-      const char* descriptor = class_initializer_black_list[i];
-      CHECK(IsValidDescriptor(descriptor)) << descriptor;
-    }
-  }
-#endif
   ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
   ParallelCompilationManager context(class_linker, jni_class_loader, this, &dex_file, thread_pool);
-  context.ForAll(0, dex_file.NumClassDefs(), InitializeClass, thread_count_);
+  size_t thread_count;
+  if (IsImage()) {
+    // TODO: remove this when transactional mode supports multithreading.
+    thread_count = 1U;
+  } else {
+    thread_count = thread_count_;
+  }
+  context.ForAll(0, dex_file.NumClassDefs(), InitializeClass, thread_count);
+  if (IsImage()) {
+    // Prune garbage objects created during aborted transactions.
+    Runtime::Current()->GetHeap()->CollectGarbage(true);
+  }
 }
 
 void CompilerDriver::InitializeClasses(jobject class_loader,
diff --git a/compiler/image_writer.cc b/compiler/image_writer.cc
index e5dfb9d..60beebb 100644
--- a/compiler/image_writer.cc
+++ b/compiler/image_writer.cc
@@ -408,25 +408,25 @@
                                                                class_linker->GetDexCaches().size());
   int i = 0;
   for (DexCache* dex_cache : class_linker->GetDexCaches()) {
-    dex_caches->Set(i++, dex_cache);
+    dex_caches->Set<false>(i++, dex_cache);
   }
 
   // build an Object[] of the roots needed to restore the runtime
   SirtRef<ObjectArray<Object> > image_roots(
       self, ObjectArray<Object>::Alloc(self, object_array_class.get(), ImageHeader::kImageRootsMax));
-  image_roots->Set(ImageHeader::kResolutionMethod, runtime->GetResolutionMethod());
-  image_roots->Set(ImageHeader::kImtConflictMethod, runtime->GetImtConflictMethod());
-  image_roots->Set(ImageHeader::kDefaultImt, runtime->GetDefaultImt());
-  image_roots->Set(ImageHeader::kCalleeSaveMethod,
-                   runtime->GetCalleeSaveMethod(Runtime::kSaveAll));
-  image_roots->Set(ImageHeader::kRefsOnlySaveMethod,
-                   runtime->GetCalleeSaveMethod(Runtime::kRefsOnly));
-  image_roots->Set(ImageHeader::kRefsAndArgsSaveMethod,
-                   runtime->GetCalleeSaveMethod(Runtime::kRefsAndArgs));
-  image_roots->Set(ImageHeader::kOatLocation,
-                   String::AllocFromModifiedUtf8(self, oat_file_->GetLocation().c_str()));
-  image_roots->Set(ImageHeader::kDexCaches, dex_caches);
-  image_roots->Set(ImageHeader::kClassRoots, class_linker->GetClassRoots());
+  image_roots->Set<false>(ImageHeader::kResolutionMethod, runtime->GetResolutionMethod());
+  image_roots->Set<false>(ImageHeader::kImtConflictMethod, runtime->GetImtConflictMethod());
+  image_roots->Set<false>(ImageHeader::kDefaultImt, runtime->GetDefaultImt());
+  image_roots->Set<false>(ImageHeader::kCalleeSaveMethod,
+                          runtime->GetCalleeSaveMethod(Runtime::kSaveAll));
+  image_roots->Set<false>(ImageHeader::kRefsOnlySaveMethod,
+                          runtime->GetCalleeSaveMethod(Runtime::kRefsOnly));
+  image_roots->Set<false>(ImageHeader::kRefsAndArgsSaveMethod,
+                          runtime->GetCalleeSaveMethod(Runtime::kRefsAndArgs));
+  image_roots->Set<false>(ImageHeader::kOatLocation,
+                          String::AllocFromModifiedUtf8(self, oat_file_->GetLocation().c_str()));
+  image_roots->Set<false>(ImageHeader::kDexCaches, dex_caches);
+  image_roots->Set<false>(ImageHeader::kClassRoots, class_linker->GetClassRoots());
   for (int i = 0; i < ImageHeader::kImageRootsMax; i++) {
     CHECK(image_roots->Get(i) != NULL);
   }
@@ -663,7 +663,7 @@
 void ImageWriter::FixupObjectArray(ObjectArray<Object>* orig, ObjectArray<Object>* copy) {
   for (int32_t i = 0; i < orig->GetLength(); ++i) {
     Object* element = orig->Get(i);
-    copy->SetWithoutChecksAndWriteBarrier(i, GetImageAddress(element));
+    copy->SetWithoutChecksAndWriteBarrier<false>(i, GetImageAddress(element));
   }
 }
 
@@ -693,7 +693,7 @@
       Object* ref = orig->GetFieldObject<Object>(byte_offset, false);
       // Use SetFieldObjectWithoutWriteBarrier to avoid card marking since we are writing to the
       // image.
-      copy->SetFieldObjectWithoutWriteBarrier(byte_offset, GetImageAddress(ref), false);
+      copy->SetFieldObjectWithoutWriteBarrier<false>(byte_offset, GetImageAddress(ref), false);
       ref_offsets &= ~(CLASS_HIGH_BIT >> right_shift);
     }
   } else {
@@ -715,7 +715,7 @@
         Object* ref = orig->GetFieldObject<Object>(field_offset, false);
         // Use SetFieldObjectWithoutWriteBarrier to avoid card marking since we are writing to the
         // image.
-        copy->SetFieldObjectWithoutWriteBarrier(field_offset, GetImageAddress(ref), false);
+        copy->SetFieldObjectWithoutWriteBarrier<false>(field_offset, GetImageAddress(ref), false);
       }
     }
   }
@@ -726,7 +726,7 @@
     Object* ref = orig->GetFieldObject<Object>(field_offset, false);
     // Use SetFieldObjectWithoutWriteBarrier to avoid card marking since we are writing to the
     // image.
-    copy->SetFieldObjectWithoutWriteBarrier(field_offset, GetImageAddress(ref), false);
+    copy->SetFieldObjectWithoutWriteBarrier<false>(field_offset, GetImageAddress(ref), false);
   }
 }
 
diff --git a/runtime/Android.mk b/runtime/Android.mk
index 223ae7c..b6b4ff9 100644
--- a/runtime/Android.mk
+++ b/runtime/Android.mk
@@ -136,6 +136,7 @@
 	thread_pool.cc \
 	throw_location.cc \
 	trace.cc \
+	transaction.cc \
 	profiler.cc \
 	utf.cc \
 	utils.cc \
diff --git a/runtime/class_linker.cc b/runtime/class_linker.cc
index fac1e14..3863ee5 100644
--- a/runtime/class_linker.cc
+++ b/runtime/class_linker.cc
@@ -2832,8 +2832,8 @@
       return nullptr;
     }
 
-    interfaces_sfield->SetObject(klass.get(), soa.Decode<mirror::ObjectArray<mirror::Class>*>(interfaces));
-    throws_sfield->SetObject(klass.get(), soa.Decode<mirror::ObjectArray<mirror::ObjectArray<mirror::Class> >*>(throws));
+    interfaces_sfield->SetObject<false>(klass.get(), soa.Decode<mirror::ObjectArray<mirror::Class>*>(interfaces));
+    throws_sfield->SetObject<false>(klass.get(), soa.Decode<mirror::ObjectArray<mirror::ObjectArray<mirror::Class> >*>(throws));
     klass->SetStatus(mirror::Class::kStatusInitialized, self);
   }
 
@@ -3144,7 +3144,11 @@
       SafeMap<uint32_t, mirror::ArtField*> field_map;
       ConstructFieldMap(dex_file, *dex_class_def, klass.get(), field_map);
       for (size_t i = 0; it.HasNext(); i++, it.Next()) {
-        it.ReadValueToField(field_map.Get(i));
+        if (Runtime::Current()->IsActiveTransaction()) {
+          it.ReadValueToField<true>(field_map.Get(i));
+        } else {
+          it.ReadValueToField<false>(field_map.Get(i));
+        }
       }
     }
   }
@@ -3530,7 +3534,7 @@
                                 super_mh.GetDeclaringClassDescriptor());
               return false;
             }
-            vtable->Set(j, local_method);
+            vtable->Set<false>(j, local_method);
             local_method->SetMethodIndex(j);
             break;
           } else {
@@ -3542,7 +3546,7 @@
       }
       if (j == actual_count) {
         // Not overriding, append.
-        vtable->Set(actual_count, local_method);
+        vtable->Set<false>(actual_count, local_method);
         local_method->SetMethodIndex(actual_count);
         actual_count += 1;
       }
@@ -3576,7 +3580,7 @@
     }
     for (size_t i = 0; i < num_virtual_methods; ++i) {
       mirror::ArtMethod* virtual_method = klass->GetVirtualMethodDuringLinking(i);
-      vtable->Set(i, virtual_method);
+      vtable->Set<false>(i, virtual_method);
       virtual_method->SetMethodIndex(i & 0xFFFF);
     }
     klass->SetVTable(vtable.get());
@@ -3745,14 +3749,14 @@
                                       PrettyMethod(interface_method).c_str());
               return false;
             }
-            method_array->Set(j, vtable_method);
+            method_array->Set<false>(j, vtable_method);
             // Place method in imt if entry is empty, place conflict otherwise.
             uint32_t imt_index = interface_method->GetDexMethodIndex() % kImtSize;
             if (imtable->Get(imt_index) == NULL) {
-              imtable->Set(imt_index, vtable_method);
+              imtable->Set<false>(imt_index, vtable_method);
               imtable_changed = true;
             } else {
-              imtable->Set(imt_index, Runtime::Current()->GetImtConflictMethod());
+              imtable->Set<false>(imt_index, Runtime::Current()->GetImtConflictMethod());
             }
             break;
           }
@@ -3777,7 +3781,7 @@
             // TODO: If a methods move then the miranda_list may hold stale references.
             miranda_list.push_back(miranda_method.get());
           }
-          method_array->Set(j, miranda_method.get());
+          method_array->Set<false>(j, miranda_method.get());
         }
       }
     }
@@ -3787,7 +3791,7 @@
     mirror::ArtMethod* imt_conflict_method = Runtime::Current()->GetImtConflictMethod();
     for (size_t i = 0; i < kImtSize; i++) {
       if (imtable->Get(i) == NULL) {
-        imtable->Set(i, imt_conflict_method);
+        imtable->Set<false>(i, imt_conflict_method);
       }
     }
     klass->SetImTable(imtable.get());
@@ -3823,7 +3827,7 @@
       method->SetAccessFlags(method->GetAccessFlags() | kAccMiranda);
       method->SetMethodIndex(0xFFFF & (old_vtable_count + i));
       klass->SetVirtualMethod(old_method_count + i, method);
-      vtable->Set(old_vtable_count + i, method);
+      vtable->Set<false>(old_vtable_count + i, method);
     }
     // TODO: do not assign to the vtable field until it is fully constructed.
     klass->SetVTable(vtable.get());
@@ -3929,7 +3933,7 @@
     }
     grouped_and_sorted_fields.pop_front();
     num_reference_fields++;
-    fields->Set(current_field, field);
+    fields->Set<false>(current_field, field);
     field->SetOffset(field_offset);
     field_offset = MemberOffset(field_offset.Uint32Value() + sizeof(uint32_t));
   }
@@ -3946,7 +3950,7 @@
       if (type == Primitive::kPrimLong || type == Primitive::kPrimDouble) {
         continue;
       }
-      fields->Set(current_field++, field);
+      fields->Set<false>(current_field++, field);
       field->SetOffset(field_offset);
       // drop the consumed field
       grouped_and_sorted_fields.erase(grouped_and_sorted_fields.begin() + i);
@@ -3965,7 +3969,7 @@
     FieldHelper fh(field);
     Primitive::Type type = fh.GetTypeAsPrimitiveType();
     CHECK(type != Primitive::kPrimNot);  // should only be working on primitive types
-    fields->Set(current_field, field);
+    fields->Set<false>(current_field, field);
     field->SetOffset(field_offset);
     field_offset = MemberOffset(field_offset.Uint32Value() +
                                 ((type == Primitive::kPrimLong || type == Primitive::kPrimDouble)
@@ -4418,7 +4422,7 @@
 
   DCHECK(class_roots_ != NULL);
   DCHECK(class_roots_->Get(class_root) == NULL);
-  class_roots_->Set(class_root, klass);
+  class_roots_->Set<false>(class_root, klass);
 }
 
 }  // namespace art
diff --git a/runtime/class_linker_test.cc b/runtime/class_linker_test.cc
index d9ef0c1..28ed6c4 100644
--- a/runtime/class_linker_test.cc
+++ b/runtime/class_linker_test.cc
@@ -867,55 +867,56 @@
   EXPECT_STREQ(ClassHelper(s0->GetClass()).GetDescriptor(), "Ljava/lang/reflect/ArtField;");
   EXPECT_TRUE(fh.GetTypeAsPrimitiveType() == Primitive::kPrimBoolean);
   EXPECT_EQ(true, s0->GetBoolean(statics.get()));
-  s0->SetBoolean(statics.get(), false);
+  s0->SetBoolean<false>(statics.get(), false);
 
   mirror::ArtField* s1 = statics->FindStaticField("s1", "B");
   fh.ChangeField(s1);
   EXPECT_TRUE(fh.GetTypeAsPrimitiveType() == Primitive::kPrimByte);
   EXPECT_EQ(5, s1->GetByte(statics.get()));
-  s1->SetByte(statics.get(), 6);
+  s1->SetByte<false>(statics.get(), 6);
 
   mirror::ArtField* s2 = statics->FindStaticField("s2", "C");
   fh.ChangeField(s2);
   EXPECT_TRUE(fh.GetTypeAsPrimitiveType() == Primitive::kPrimChar);
   EXPECT_EQ('a', s2->GetChar(statics.get()));
-  s2->SetChar(statics.get(), 'b');
+  s2->SetChar<false>(statics.get(), 'b');
 
   mirror::ArtField* s3 = statics->FindStaticField("s3", "S");
   fh.ChangeField(s3);
   EXPECT_TRUE(fh.GetTypeAsPrimitiveType() == Primitive::kPrimShort);
   EXPECT_EQ(-536, s3->GetShort(statics.get()));
-  s3->SetShort(statics.get(), -535);
+  s3->SetShort<false>(statics.get(), -535);
 
   mirror::ArtField* s4 = statics->FindStaticField("s4", "I");
   fh.ChangeField(s4);
   EXPECT_TRUE(fh.GetTypeAsPrimitiveType() == Primitive::kPrimInt);
   EXPECT_EQ(2000000000, s4->GetInt(statics.get()));
-  s4->SetInt(statics.get(), 2000000001);
+  s4->SetInt<false>(statics.get(), 2000000001);
 
   mirror::ArtField* s5 = statics->FindStaticField("s5", "J");
   fh.ChangeField(s5);
   EXPECT_TRUE(fh.GetTypeAsPrimitiveType() == Primitive::kPrimLong);
   EXPECT_EQ(0x1234567890abcdefLL, s5->GetLong(statics.get()));
-  s5->SetLong(statics.get(), 0x34567890abcdef12LL);
+  s5->SetLong<false>(statics.get(), 0x34567890abcdef12LL);
 
   mirror::ArtField* s6 = statics->FindStaticField("s6", "F");
   fh.ChangeField(s6);
   EXPECT_TRUE(fh.GetTypeAsPrimitiveType() == Primitive::kPrimFloat);
   EXPECT_EQ(0.5, s6->GetFloat(statics.get()));
-  s6->SetFloat(statics.get(), 0.75);
+  s6->SetFloat<false>(statics.get(), 0.75);
 
   mirror::ArtField* s7 = statics->FindStaticField("s7", "D");
   fh.ChangeField(s7);
   EXPECT_TRUE(fh.GetTypeAsPrimitiveType() == Primitive::kPrimDouble);
   EXPECT_EQ(16777217, s7->GetDouble(statics.get()));
-  s7->SetDouble(statics.get(), 16777219);
+  s7->SetDouble<false>(statics.get(), 16777219);
 
   mirror::ArtField* s8 = statics->FindStaticField("s8", "Ljava/lang/String;");
   fh.ChangeField(s8);
   EXPECT_TRUE(fh.GetTypeAsPrimitiveType() == Primitive::kPrimNot);
   EXPECT_TRUE(s8->GetObject(statics.get())->AsString()->Equals("android"));
-  s8->SetObject(s8->GetDeclaringClass(), mirror::String::AllocFromModifiedUtf8(soa.Self(), "robot"));
+  s8->SetObject<false>(s8->GetDeclaringClass(),
+                       mirror::String::AllocFromModifiedUtf8(soa.Self(), "robot"));
 
   // TODO: Remove EXPECT_FALSE when GCC can handle EXPECT_EQ
   // http://code.google.com/p/googletest/issues/detail?id=322
diff --git a/runtime/debugger.cc b/runtime/debugger.cc
index 733e843..20ad372 100644
--- a/runtime/debugger.cc
+++ b/runtime/debugger.cc
@@ -1149,7 +1149,7 @@
       if (o == ObjectRegistry::kInvalidObject) {
         return JDWP::ERR_INVALID_OBJECT;
       }
-      oa->Set(offset + i, o);
+      oa->Set<false>(offset + i, o);
     }
   }
 
@@ -1582,10 +1582,12 @@
   if (IsPrimitiveTag(tag)) {
     if (tag == JDWP::JT_DOUBLE || tag == JDWP::JT_LONG) {
       CHECK_EQ(width, 8);
-      f->Set64(o, value);
+      // Debugging can't use transactional mode (runtime only).
+      f->Set64<false>(o, value);
     } else {
       CHECK_LE(width, 4);
-      f->Set32(o, value);
+      // Debugging can't use transactional mode (runtime only).
+      f->Set32<false>(o, value);
     }
   } else {
     mirror::Object* v = gRegistry->Get<mirror::Object*>(value);
@@ -1598,7 +1600,8 @@
         return JDWP::ERR_INVALID_OBJECT;
       }
     }
-    f->SetObject(o, v);
+    // Debugging can't use transactional mode (runtime only).
+    f->SetObject<false>(o, v);
   }
 
   return JDWP::ERR_NONE;
diff --git a/runtime/dex_file.cc b/runtime/dex_file.cc
index eaba7eb..5e2b9ff 100644
--- a/runtime/dex_file.cc
+++ b/runtime/dex_file.cc
@@ -1082,33 +1082,36 @@
   ptr_ += width;
 }
 
+template<bool kTransactionActive>
 void EncodedStaticFieldValueIterator::ReadValueToField(mirror::ArtField* field) const {
   switch (type_) {
-    case kBoolean: field->SetBoolean(field->GetDeclaringClass(), jval_.z); break;
-    case kByte:    field->SetByte(field->GetDeclaringClass(), jval_.b); break;
-    case kShort:   field->SetShort(field->GetDeclaringClass(), jval_.s); break;
-    case kChar:    field->SetChar(field->GetDeclaringClass(), jval_.c); break;
-    case kInt:     field->SetInt(field->GetDeclaringClass(), jval_.i); break;
-    case kLong:    field->SetLong(field->GetDeclaringClass(), jval_.j); break;
-    case kFloat:   field->SetFloat(field->GetDeclaringClass(), jval_.f); break;
-    case kDouble:  field->SetDouble(field->GetDeclaringClass(), jval_.d); break;
-    case kNull:    field->SetObject(field->GetDeclaringClass(), NULL); break;
+    case kBoolean: field->SetBoolean<kTransactionActive>(field->GetDeclaringClass(), jval_.z); break;
+    case kByte:    field->SetByte<kTransactionActive>(field->GetDeclaringClass(), jval_.b); break;
+    case kShort:   field->SetShort<kTransactionActive>(field->GetDeclaringClass(), jval_.s); break;
+    case kChar:    field->SetChar<kTransactionActive>(field->GetDeclaringClass(), jval_.c); break;
+    case kInt:     field->SetInt<kTransactionActive>(field->GetDeclaringClass(), jval_.i); break;
+    case kLong:    field->SetLong<kTransactionActive>(field->GetDeclaringClass(), jval_.j); break;
+    case kFloat:   field->SetFloat<kTransactionActive>(field->GetDeclaringClass(), jval_.f); break;
+    case kDouble:  field->SetDouble<kTransactionActive>(field->GetDeclaringClass(), jval_.d); break;
+    case kNull:    field->SetObject<kTransactionActive>(field->GetDeclaringClass(), NULL); break;
     case kString: {
       CHECK(!kMovingFields);
       mirror::String* resolved = linker_->ResolveString(dex_file_, jval_.i, *dex_cache_);
-      field->SetObject(field->GetDeclaringClass(), resolved);
+      field->SetObject<kTransactionActive>(field->GetDeclaringClass(), resolved);
       break;
     }
     case kType: {
       CHECK(!kMovingFields);
       mirror::Class* resolved = linker_->ResolveType(dex_file_, jval_.i, *dex_cache_,
                                                      *class_loader_);
-      field->SetObject(field->GetDeclaringClass(), resolved);
+      field->SetObject<kTransactionActive>(field->GetDeclaringClass(), resolved);
       break;
     }
     default: UNIMPLEMENTED(FATAL) << ": type " << type_;
   }
 }
+template void EncodedStaticFieldValueIterator::ReadValueToField<true>(mirror::ArtField* field) const;
+template void EncodedStaticFieldValueIterator::ReadValueToField<false>(mirror::ArtField* field) const;
 
 CatchHandlerIterator::CatchHandlerIterator(const DexFile::CodeItem& code_item, uint32_t address) {
   handler_.address_ = -1;
diff --git a/runtime/dex_file.h b/runtime/dex_file.h
index 46df455..e9d18b5 100644
--- a/runtime/dex_file.h
+++ b/runtime/dex_file.h
@@ -1142,6 +1142,7 @@
                                   ClassLinker* linker, const DexFile::ClassDef& class_def)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
+  template<bool kTransactionActive>
   void ReadValueToField(mirror::ArtField* field) const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
   bool HasNext() { return pos_ < array_size_; }
diff --git a/runtime/entrypoints/entrypoint_utils.cc b/runtime/entrypoints/entrypoint_utils.cc
index 4e58a72..4078cac 100644
--- a/runtime/entrypoints/entrypoint_utils.cc
+++ b/runtime/entrypoints/entrypoint_utils.cc
@@ -162,7 +162,7 @@
           CHECK(soa.Self()->IsExceptionPending());
           return zero;
         }
-        soa.Decode<mirror::ObjectArray<mirror::Object>* >(args_jobj)->Set(i, val);
+        soa.Decode<mirror::ObjectArray<mirror::Object>* >(args_jobj)->Set<false>(i, val);
       }
     }
   }
diff --git a/runtime/entrypoints/entrypoint_utils.h b/runtime/entrypoints/entrypoint_utils.h
index c3deba5..8b94b5a 100644
--- a/runtime/entrypoints/entrypoint_utils.h
+++ b/runtime/entrypoints/entrypoint_utils.h
@@ -136,6 +136,7 @@
     gc::Heap* heap = Runtime::Current()->GetHeap();
     return klass->Alloc<kInstrumented>(self, heap->GetCurrentAllocator());
   }
+  DCHECK(klass != nullptr);
   return klass->Alloc<kInstrumented>(self, allocator_type);
 }
 
diff --git a/runtime/entrypoints/portable/portable_field_entrypoints.cc b/runtime/entrypoints/portable/portable_field_entrypoints.cc
index 0b54b9c..f48f1a9 100644
--- a/runtime/entrypoints/portable/portable_field_entrypoints.cc
+++ b/runtime/entrypoints/portable/portable_field_entrypoints.cc
@@ -30,13 +30,15 @@
                                StaticPrimitiveWrite,
                                sizeof(uint32_t));
   if (LIKELY(field != NULL)) {
-    field->Set32(field->GetDeclaringClass(), new_value);
+    // Compiled code can't use transactional mode.
+    field->Set32<false>(field->GetDeclaringClass(), new_value);
     return 0;
   }
   field = FindFieldFromCode<StaticPrimitiveWrite, true>(field_idx, referrer, Thread::Current(),
                                                         sizeof(uint32_t));
   if (LIKELY(field != NULL)) {
-    field->Set32(field->GetDeclaringClass(), new_value);
+    // Compiled code can't use transactional mode.
+    field->Set32<false>(field->GetDeclaringClass(), new_value);
     return 0;
   }
   return -1;
@@ -48,13 +50,15 @@
     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
   mirror::ArtField* field = FindFieldFast(field_idx, referrer, StaticPrimitiveWrite, sizeof(uint64_t));
   if (LIKELY(field != NULL)) {
-    field->Set64(field->GetDeclaringClass(), new_value);
+    // Compiled code can't use transactional mode.
+    field->Set64<false>(field->GetDeclaringClass(), new_value);
     return 0;
   }
   field = FindFieldFromCode<StaticPrimitiveWrite, true>(field_idx, referrer, Thread::Current(),
                                                         sizeof(uint64_t));
   if (LIKELY(field != NULL)) {
-    field->Set64(field->GetDeclaringClass(), new_value);
+    // Compiled code can't use transactional mode.
+    field->Set64<false>(field->GetDeclaringClass(), new_value);
     return 0;
   }
   return -1;
@@ -67,13 +71,15 @@
   mirror::ArtField* field = FindFieldFast(field_idx, referrer, StaticObjectWrite,
                                           sizeof(mirror::HeapReference<mirror::Object>));
   if (LIKELY(field != NULL)) {
-    field->SetObj(field->GetDeclaringClass(), new_value);
+    // Compiled code can't use transactional mode.
+    field->SetObj<false>(field->GetDeclaringClass(), new_value);
     return 0;
   }
   field = FindFieldFromCode<StaticObjectWrite, true>(field_idx, referrer, Thread::Current(),
                                                      sizeof(mirror::HeapReference<mirror::Object>));
   if (LIKELY(field != NULL)) {
-    field->SetObj(field->GetDeclaringClass(), new_value);
+    // Compiled code can't use transactional mode.
+    field->SetObj<false>(field->GetDeclaringClass(), new_value);
     return 0;
   }
   return -1;
@@ -131,13 +137,15 @@
     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
   mirror::ArtField* field = FindFieldFast(field_idx, referrer, InstancePrimitiveWrite, sizeof(uint32_t));
   if (LIKELY(field != NULL)) {
-    field->Set32(obj, new_value);
+    // Compiled code can't use transactional mode.
+    field->Set32<false>(obj, new_value);
     return 0;
   }
   field = FindFieldFromCode<InstancePrimitiveWrite, true>(field_idx, referrer, Thread::Current(),
                                                           sizeof(uint32_t));
   if (LIKELY(field != NULL)) {
-    field->Set32(obj, new_value);
+    // Compiled code can't use transactional mode.
+    field->Set32<false>(obj, new_value);
     return 0;
   }
   return -1;
@@ -149,13 +157,15 @@
     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
   mirror::ArtField* field = FindFieldFast(field_idx, referrer, InstancePrimitiveWrite, sizeof(uint64_t));
   if (LIKELY(field != NULL)) {
-    field->Set64(obj, new_value);
+    // Compiled code can't use transactional mode.
+    field->Set64<false>(obj, new_value);
     return 0;
   }
   field = FindFieldFromCode<InstancePrimitiveWrite, true>(field_idx, referrer, Thread::Current(),
                                                           sizeof(uint64_t));
   if (LIKELY(field != NULL)) {
-    field->Set64(obj, new_value);
+    // Compiled code can't use transactional mode.
+    field->Set64<false>(obj, new_value);
     return 0;
   }
   return -1;
@@ -169,13 +179,15 @@
   mirror::ArtField* field = FindFieldFast(field_idx, referrer, InstanceObjectWrite,
                                           sizeof(mirror::HeapReference<mirror::Object>));
   if (LIKELY(field != NULL)) {
-    field->SetObj(obj, new_value);
+    // Compiled code can't use transactional mode.
+    field->SetObj<false>(obj, new_value);
     return 0;
   }
   field = FindFieldFromCode<InstanceObjectWrite, true>(field_idx, referrer, Thread::Current(),
                                                        sizeof(mirror::HeapReference<mirror::Object>));
   if (LIKELY(field != NULL)) {
-    field->SetObj(obj, new_value);
+    // Compiled code can't use transactional mode.
+    field->SetObj<false>(obj, new_value);
     return 0;
   }
   return -1;
diff --git a/runtime/entrypoints/quick/quick_field_entrypoints.cc b/runtime/entrypoints/quick/quick_field_entrypoints.cc
index 93ff7aa..2d5c07d 100644
--- a/runtime/entrypoints/quick/quick_field_entrypoints.cc
+++ b/runtime/entrypoints/quick/quick_field_entrypoints.cc
@@ -154,13 +154,15 @@
   mirror::ArtField* field = FindFieldFast(field_idx, referrer, StaticPrimitiveWrite,
                                           sizeof(int32_t));
   if (LIKELY(field != NULL)) {
-    field->Set32(field->GetDeclaringClass(), new_value);
+    // Compiled code can't use transactional mode.
+    field->Set32<false>(field->GetDeclaringClass(), new_value);
     return 0;  // success
   }
   FinishCalleeSaveFrameSetup(self, sp, Runtime::kRefsOnly);
   field = FindFieldFromCode<StaticPrimitiveWrite, true>(field_idx, referrer, self, sizeof(int32_t));
   if (LIKELY(field != NULL)) {
-    field->Set32(field->GetDeclaringClass(), new_value);
+    // Compiled code can't use transactional mode.
+    field->Set32<false>(field->GetDeclaringClass(), new_value);
     return 0;  // success
   }
   return -1;  // failure
@@ -172,13 +174,15 @@
   mirror::ArtField* field = FindFieldFast(field_idx, referrer, StaticPrimitiveWrite,
                                           sizeof(int64_t));
   if (LIKELY(field != NULL)) {
-    field->Set64(field->GetDeclaringClass(), new_value);
+    // Compiled code can't use transactional mode.
+    field->Set64<false>(field->GetDeclaringClass(), new_value);
     return 0;  // success
   }
   FinishCalleeSaveFrameSetup(self, sp, Runtime::kRefsOnly);
   field = FindFieldFromCode<StaticPrimitiveWrite, true>(field_idx, referrer, self, sizeof(int64_t));
   if (LIKELY(field != NULL)) {
-    field->Set64(field->GetDeclaringClass(), new_value);
+    // Compiled code can't use transactional mode.
+    field->Set64<false>(field->GetDeclaringClass(), new_value);
     return 0;  // success
   }
   return -1;  // failure
@@ -192,7 +196,8 @@
                                           sizeof(mirror::HeapReference<mirror::Object>));
   if (LIKELY(field != NULL)) {
     if (LIKELY(!FieldHelper(field).IsPrimitiveType())) {
-      field->SetObj(field->GetDeclaringClass(), new_value);
+      // Compiled code can't use transactional mode.
+      field->SetObj<false>(field->GetDeclaringClass(), new_value);
       return 0;  // success
     }
   }
@@ -200,7 +205,8 @@
   field = FindFieldFromCode<StaticObjectWrite, true>(field_idx, referrer, self,
                                                      sizeof(mirror::HeapReference<mirror::Object>));
   if (LIKELY(field != NULL)) {
-    field->SetObj(field->GetDeclaringClass(), new_value);
+    // Compiled code can't use transactional mode.
+    field->SetObj<false>(field->GetDeclaringClass(), new_value);
     return 0;  // success
   }
   return -1;  // failure
@@ -213,7 +219,8 @@
   mirror::ArtField* field = FindFieldFast(field_idx, referrer, InstancePrimitiveWrite,
                                           sizeof(int32_t));
   if (LIKELY(field != NULL && obj != NULL)) {
-    field->Set32(obj, new_value);
+    // Compiled code can't use transactional mode.
+    field->Set32<false>(obj, new_value);
     return 0;  // success
   }
   FinishCalleeSaveFrameSetup(self, sp, Runtime::kRefsOnly);
@@ -224,7 +231,8 @@
       ThrowLocation throw_location = self->GetCurrentLocationForThrow();
       ThrowNullPointerExceptionForFieldAccess(throw_location, field, false);
     } else {
-      field->Set32(obj, new_value);
+      // Compiled code can't use transactional mode.
+      field->Set32<false>(obj, new_value);
       return 0;  // success
     }
   }
@@ -240,7 +248,8 @@
   mirror::ArtField* field = FindFieldFast(field_idx, referrer, InstancePrimitiveWrite,
                                           sizeof(int64_t));
   if (LIKELY(field != NULL  && obj != NULL)) {
-    field->Set64(obj, new_value);
+    // Compiled code can't use transactional mode.
+    field->Set64<false>(obj, new_value);
     return 0;  // success
   }
   *sp = callee_save;
@@ -252,7 +261,8 @@
       ThrowLocation throw_location = self->GetCurrentLocationForThrow();
       ThrowNullPointerExceptionForFieldAccess(throw_location, field, false);
     } else {
-      field->Set64(obj, new_value);
+      // Compiled code can't use transactional mode.
+      field->Set64<false>(obj, new_value);
       return 0;  // success
     }
   }
@@ -267,7 +277,8 @@
   mirror::ArtField* field = FindFieldFast(field_idx, referrer, InstanceObjectWrite,
                                           sizeof(mirror::HeapReference<mirror::Object>));
   if (LIKELY(field != NULL && obj != NULL)) {
-    field->SetObj(obj, new_value);
+    // Compiled code can't use transactional mode.
+    field->SetObj<false>(obj, new_value);
     return 0;  // success
   }
   FinishCalleeSaveFrameSetup(self, sp, Runtime::kRefsOnly);
@@ -278,7 +289,8 @@
       ThrowLocation throw_location = self->GetCurrentLocationForThrow();
       ThrowNullPointerExceptionForFieldAccess(throw_location, field, false);
     } else {
-      field->SetObj(obj, new_value);
+      // Compiled code can't use transactional mode.
+      field->SetObj<false>(obj, new_value);
       return 0;  // success
     }
   }
diff --git a/runtime/entrypoints/quick/quick_trampoline_entrypoints.cc b/runtime/entrypoints/quick/quick_trampoline_entrypoints.cc
index f9486c3..012dabb 100644
--- a/runtime/entrypoints/quick/quick_trampoline_entrypoints.cc
+++ b/runtime/entrypoints/quick/quick_trampoline_entrypoints.cc
@@ -558,7 +558,7 @@
       // We came here because of sharpening. Ensure the dex cache is up-to-date on the method index
       // of the sharpened method.
       if (called->GetDexCacheResolvedMethods() == caller->GetDexCacheResolvedMethods()) {
-        caller->GetDexCacheResolvedMethods()->Set(called->GetDexMethodIndex(), called);
+        caller->GetDexCacheResolvedMethods()->Set<false>(called->GetDexMethodIndex(), called);
       } else {
         // Calling from one dex file to another, need to compute the method index appropriate to
         // the caller's dex file. Since we get here only if the original called was a runtime
@@ -567,7 +567,7 @@
         uint32_t method_index =
             MethodHelper(called).FindDexMethodIndexInOtherDexFile(*dex_file, dex_method_idx);
         if (method_index != DexFile::kDexNoIndex) {
-          caller->GetDexCacheResolvedMethods()->Set(method_index, called);
+          caller->GetDexCacheResolvedMethods()->Set<false>(method_index, called);
         }
       }
     }
diff --git a/runtime/gc/accounting/mod_union_table.cc b/runtime/gc/accounting/mod_union_table.cc
index aad214a..6258070 100644
--- a/runtime/gc/accounting/mod_union_table.cc
+++ b/runtime/gc/accounting/mod_union_table.cc
@@ -84,7 +84,11 @@
       if (new_ref != ref) {
         // Use SetFieldObjectWithoutWriteBarrier to avoid card mark as an optimization which
         // reduces dirtied pages and improves performance.
-        obj->SetFieldObjectWithoutWriteBarrier(offset, new_ref, true);
+        if (Runtime::Current()->IsActiveTransaction()) {
+          obj->SetFieldObjectWithoutWriteBarrier<true>(offset, new_ref, true);
+        } else {
+          obj->SetFieldObjectWithoutWriteBarrier<false>(offset, new_ref, true);
+        }
       }
     }
   }
diff --git a/runtime/gc/collector/semi_space.cc b/runtime/gc/collector/semi_space.cc
index b1122b9..6d9496e 100644
--- a/runtime/gc/collector/semi_space.cc
+++ b/runtime/gc/collector/semi_space.cc
@@ -662,7 +662,9 @@
       // Don't need to mark the card since we updating the object address and not changing the
       // actual objects its pointing to. Using SetFieldObjectWithoutWriteBarrier is better in this
       // case since it does not dirty cards and use additional memory.
-      obj->SetFieldObjectWithoutWriteBarrier(offset, new_address, false);
+      // Since we do not change the actual object, we can safely use non-transactional mode. Also
+      // disable check as we could run inside a transaction.
+      obj->SetFieldObjectWithoutWriteBarrier<false, false>(offset, new_address, false);
     }
   }, kMovingClasses);
   mirror::Class* klass = obj->GetClass();
diff --git a/runtime/gc/heap.cc b/runtime/gc/heap.cc
index f1126ef..7613a31 100644
--- a/runtime/gc/heap.cc
+++ b/runtime/gc/heap.cc
@@ -2335,7 +2335,7 @@
 void Heap::SetReferenceReferent(mirror::Object* reference, mirror::Object* referent) {
   DCHECK(reference != NULL);
   DCHECK_NE(reference_referent_offset_.Uint32Value(), 0U);
-  reference->SetFieldObject(reference_referent_offset_, referent, true);
+  reference->SetFieldObject<false, false>(reference_referent_offset_, referent, true);
 }
 
 mirror::Object* Heap::GetReferenceReferent(mirror::Object* reference) {
diff --git a/runtime/gc/heap_test.cc b/runtime/gc/heap_test.cc
index 8af2725..b02b8bb 100644
--- a/runtime/gc/heap_test.cc
+++ b/runtime/gc/heap_test.cc
@@ -50,7 +50,7 @@
       for (size_t j = 0; j < 2048; ++j) {
         mirror::String* string = mirror::String::AllocFromModifiedUtf8(soa.Self(), "hello, world!");
         // SIRT operator -> deferences the SIRT before running the method.
-        array->Set(j, string);
+        array->Set<false>(j, string);
       }
     }
   }
diff --git a/runtime/gc/reference_queue.cc b/runtime/gc/reference_queue.cc
index fae4cac..203701f 100644
--- a/runtime/gc/reference_queue.cc
+++ b/runtime/gc/reference_queue.cc
@@ -49,12 +49,21 @@
   DCHECK_NE(pending_next_offset.Uint32Value(), 0U);
   if (IsEmpty()) {
     // 1 element cyclic queue, ie: Reference ref = ..; ref.pendingNext = ref;
-    ref->SetFieldObject(pending_next_offset, ref, false);
+    if (Runtime::Current()->IsActiveTransaction()) {
+      ref->SetFieldObject<true>(pending_next_offset, ref, false);
+    } else {
+      ref->SetFieldObject<false>(pending_next_offset, ref, false);
+    }
     list_ = ref;
   } else {
     mirror::Object* head = list_->GetFieldObject<mirror::Object>(pending_next_offset, false);
-    ref->SetFieldObject(pending_next_offset, head, false);
-    list_->SetFieldObject(pending_next_offset, ref, false);
+    if (Runtime::Current()->IsActiveTransaction()) {
+      ref->SetFieldObject<true>(pending_next_offset, head, false);
+      list_->SetFieldObject<true>(pending_next_offset, ref, false);
+    } else {
+      ref->SetFieldObject<false>(pending_next_offset, head, false);
+      list_->SetFieldObject<false>(pending_next_offset, ref, false);
+    }
   }
 }
 
@@ -71,10 +80,18 @@
     list_ = nullptr;
   } else {
     mirror::Object* next = head->GetFieldObject<mirror::Object>(pending_next_offset, false);
-    list_->SetFieldObject(pending_next_offset, next, false);
+    if (Runtime::Current()->IsActiveTransaction()) {
+      list_->SetFieldObject<true>(pending_next_offset, next, false);
+    } else {
+      list_->SetFieldObject<false>(pending_next_offset, next, false);
+    }
     ref = head;
   }
-  ref->SetFieldObject(pending_next_offset, nullptr, false);
+  if (Runtime::Current()->IsActiveTransaction()) {
+    ref->SetFieldObject<true>(pending_next_offset, nullptr, false);
+  } else {
+    ref->SetFieldObject<false>(pending_next_offset, nullptr, false);
+  }
   return ref;
 }
 
@@ -131,7 +148,11 @@
         // If the referent is non-null the reference must queuable.
         DCHECK(heap_->IsEnqueuable(ref));
         // Move the updated referent to the zombie field.
-        ref->SetFieldObject(heap_->GetFinalizerReferenceZombieOffset(), forward_address, false);
+        if (Runtime::Current()->IsActiveTransaction()) {
+          ref->SetFieldObject<true>(heap_->GetFinalizerReferenceZombieOffset(), forward_address, false);
+        } else {
+          ref->SetFieldObject<false>(heap_->GetFinalizerReferenceZombieOffset(), forward_address, false);
+        }
         heap_->ClearReferenceReferent(ref);
         cleared_references.EnqueueReference(ref);
       } else if (referent != forward_address) {
diff --git a/runtime/intern_table.cc b/runtime/intern_table.cc
index 5693747..cc49d67 100644
--- a/runtime/intern_table.cc
+++ b/runtime/intern_table.cc
@@ -28,24 +28,24 @@
 namespace art {
 
 InternTable::InternTable()
-    : intern_table_lock_("InternTable lock"), is_dirty_(false), allow_new_interns_(true),
-      new_intern_condition_("New intern condition", intern_table_lock_) {
+    : is_dirty_(false), allow_new_interns_(true),
+      new_intern_condition_("New intern condition", *Locks::intern_table_lock_) {
 }
 
 size_t InternTable::Size() const {
-  MutexLock mu(Thread::Current(), intern_table_lock_);
+  MutexLock mu(Thread::Current(), *Locks::intern_table_lock_);
   return strong_interns_.size() + weak_interns_.size();
 }
 
 void InternTable::DumpForSigQuit(std::ostream& os) const {
-  MutexLock mu(Thread::Current(), intern_table_lock_);
+  MutexLock mu(Thread::Current(), *Locks::intern_table_lock_);
   os << "Intern table: " << strong_interns_.size() << " strong; "
      << weak_interns_.size() << " weak\n";
 }
 
 void InternTable::VisitRoots(RootCallback* callback, void* arg,
                              bool only_dirty, bool clean_dirty) {
-  MutexLock mu(Thread::Current(), intern_table_lock_);
+  MutexLock mu(Thread::Current(), *Locks::intern_table_lock_);
   if (!only_dirty || is_dirty_) {
     for (auto& strong_intern : strong_interns_) {
       strong_intern.second =
@@ -61,7 +61,7 @@
 }
 
 mirror::String* InternTable::Lookup(Table& table, mirror::String* s, uint32_t hash_code) {
-  intern_table_lock_.AssertHeld(Thread::Current());
+  Locks::intern_table_lock_->AssertHeld(Thread::Current());
   for (auto it = table.find(hash_code), end = table.end(); it != end; ++it) {
     mirror::String* existing_string = it->second;
     if (existing_string->Equals(s)) {
@@ -71,15 +71,38 @@
   return NULL;
 }
 
+mirror::String* InternTable::InsertStrong(mirror::String* s, uint32_t hash_code) {
+  Runtime* runtime = Runtime::Current();
+  if (runtime->IsActiveTransaction()) {
+    runtime->RecordStrongStringInsertion(s, hash_code);
+  }
+  return Insert(strong_interns_, s, hash_code);
+}
+
+mirror::String* InternTable::InsertWeak(mirror::String* s, uint32_t hash_code) {
+  Runtime* runtime = Runtime::Current();
+  if (runtime->IsActiveTransaction()) {
+    runtime->RecordWeakStringInsertion(s, hash_code);
+  }
+  return Insert(weak_interns_, s, hash_code);
+}
+
 mirror::String* InternTable::Insert(Table& table, mirror::String* s, uint32_t hash_code) {
-  intern_table_lock_.AssertHeld(Thread::Current());
+  Locks::intern_table_lock_->AssertHeld(Thread::Current());
   table.insert(std::make_pair(hash_code, s));
   return s;
 }
 
-void InternTable::Remove(Table& table, const mirror::String* s,
-                         uint32_t hash_code) {
-  intern_table_lock_.AssertHeld(Thread::Current());
+void InternTable::RemoveWeak(mirror::String* s, uint32_t hash_code) {
+  Runtime* runtime = Runtime::Current();
+  if (runtime->IsActiveTransaction()) {
+    runtime->RecordWeakStringRemoval(s, hash_code);
+  }
+  Remove(weak_interns_, s, hash_code);
+}
+
+void InternTable::Remove(Table& table, mirror::String* s, uint32_t hash_code) {
+  Locks::intern_table_lock_->AssertHeld(Thread::Current());
   for (auto it = table.find(hash_code), end = table.end(); it != end; ++it) {
     if (it->second == s) {
       table.erase(it);
@@ -88,6 +111,24 @@
   }
 }
 
+// Insert/remove methods used to undo changes made during an aborted transaction.
+mirror::String* InternTable::InsertStrongFromTransaction(mirror::String* s, uint32_t hash_code) {
+  DCHECK(!Runtime::Current()->IsActiveTransaction());
+  return InsertStrong(s, hash_code);
+}
+mirror::String* InternTable::InsertWeakFromTransaction(mirror::String* s, uint32_t hash_code) {
+  DCHECK(!Runtime::Current()->IsActiveTransaction());
+  return InsertWeak(s, hash_code);
+}
+void InternTable::RemoveStrongFromTransaction(mirror::String* s, uint32_t hash_code) {
+  DCHECK(!Runtime::Current()->IsActiveTransaction());
+  Remove(strong_interns_, s, hash_code);
+}
+void InternTable::RemoveWeakFromTransaction(mirror::String* s, uint32_t hash_code) {
+  DCHECK(!Runtime::Current()->IsActiveTransaction());
+  Remove(weak_interns_, s, hash_code);
+}
+
 static mirror::String* LookupStringFromImage(mirror::String* s)
     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
   gc::space::ImageSpace* image = Runtime::Current()->GetHeap()->GetImageSpace();
@@ -115,20 +156,20 @@
 
 void InternTable::AllowNewInterns() {
   Thread* self = Thread::Current();
-  MutexLock mu(self, intern_table_lock_);
+  MutexLock mu(self, *Locks::intern_table_lock_);
   allow_new_interns_ = true;
   new_intern_condition_.Broadcast(self);
 }
 
 void InternTable::DisallowNewInterns() {
   Thread* self = Thread::Current();
-  MutexLock mu(self, intern_table_lock_);
+  MutexLock mu(self, *Locks::intern_table_lock_);
   allow_new_interns_ = false;
 }
 
 mirror::String* InternTable::Insert(mirror::String* s, bool is_strong) {
   Thread* self = Thread::Current();
-  MutexLock mu(self, intern_table_lock_);
+  MutexLock mu(self, *Locks::intern_table_lock_);
 
   DCHECK(s != NULL);
   uint32_t hash_code = s->GetHashCode();
@@ -150,20 +191,20 @@
     // Check the image for a match.
     mirror::String* image = LookupStringFromImage(s);
     if (image != NULL) {
-      return Insert(strong_interns_, image, hash_code);
+      return InsertStrong(image, hash_code);
     }
 
     // There is no match in the strong table, check the weak table.
     mirror::String* weak = Lookup(weak_interns_, s, hash_code);
     if (weak != NULL) {
       // A match was found in the weak table. Promote to the strong table.
-      Remove(weak_interns_, weak, hash_code);
-      return Insert(strong_interns_, weak, hash_code);
+      RemoveWeak(weak, hash_code);
+      return InsertStrong(weak, hash_code);
     }
 
     // No match in the strong table or the weak table. Insert into the strong
     // table.
-    return Insert(strong_interns_, s, hash_code);
+    return InsertStrong(s, hash_code);
   }
 
   // Check the strong table for a match.
@@ -174,7 +215,7 @@
   // Check the image for a match.
   mirror::String* image = LookupStringFromImage(s);
   if (image != NULL) {
-    return Insert(weak_interns_, image, hash_code);
+    return InsertWeak(image, hash_code);
   }
   // Check the weak table for a match.
   mirror::String* weak = Lookup(weak_interns_, s, hash_code);
@@ -182,7 +223,7 @@
     return weak;
   }
   // Insert into the weak table.
-  return Insert(weak_interns_, s, hash_code);
+  return InsertWeak(s, hash_code);
 }
 
 mirror::String* InternTable::InternStrong(int32_t utf16_length,
@@ -211,13 +252,13 @@
 }
 
 bool InternTable::ContainsWeak(mirror::String* s) {
-  MutexLock mu(Thread::Current(), intern_table_lock_);
+  MutexLock mu(Thread::Current(), *Locks::intern_table_lock_);
   const mirror::String* found = Lookup(weak_interns_, s, s->GetHashCode());
   return found == s;
 }
 
 void InternTable::SweepInternTableWeaks(IsMarkedCallback* callback, void* arg) {
-  MutexLock mu(Thread::Current(), intern_table_lock_);
+  MutexLock mu(Thread::Current(), *Locks::intern_table_lock_);
   for (auto it = weak_interns_.begin(), end = weak_interns_.end(); it != end;) {
     mirror::Object* object = it->second;
     mirror::Object* new_object = callback(object, arg);
diff --git a/runtime/intern_table.h b/runtime/intern_table.h
index 9f09fb9..cc48480 100644
--- a/runtime/intern_table.h
+++ b/runtime/intern_table.h
@@ -18,6 +18,7 @@
 #define ART_RUNTIME_INTERN_TABLE_H_
 
 #include "base/mutex.h"
+#include "locks.h"
 #include "object_callbacks.h"
 
 #include <map>
@@ -26,6 +27,7 @@
 namespace mirror {
 class String;
 }  // namespace mirror
+class Transaction;
 
 /**
  * Used to intern strings.
@@ -72,19 +74,38 @@
   typedef std::multimap<int32_t, mirror::String*> Table;
 
   mirror::String* Insert(mirror::String* s, bool is_strong)
+      LOCKS_EXCLUDED(Locks::intern_table_lock_)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
   mirror::String* Lookup(Table& table, mirror::String* s, uint32_t hash_code)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
-  mirror::String* Insert(Table& table, mirror::String* s, uint32_t hash_code);
-  void Remove(Table& table, const mirror::String* s, uint32_t hash_code);
+  mirror::String* InsertStrong(mirror::String* s, uint32_t hash_code)
+      EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_);
+  mirror::String* InsertWeak(mirror::String* s, uint32_t hash_code)
+      EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_);
+  mirror::String* Insert(Table& table, mirror::String* s, uint32_t hash_code)
+      EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_);
+  void RemoveWeak(mirror::String* s, uint32_t hash_code)
+      EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_);
+  void Remove(Table& table, mirror::String* s, uint32_t hash_code)
+      EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_);
 
-  mutable Mutex intern_table_lock_;
-  bool is_dirty_ GUARDED_BY(intern_table_lock_);
-  bool allow_new_interns_ GUARDED_BY(intern_table_lock_);
-  ConditionVariable new_intern_condition_ GUARDED_BY(intern_table_lock_);
-  Table strong_interns_ GUARDED_BY(intern_table_lock_);
-  Table weak_interns_ GUARDED_BY(intern_table_lock_);
+  // Transaction rollback access.
+  mirror::String* InsertStrongFromTransaction(mirror::String* s, uint32_t hash_code)
+      EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_);
+  mirror::String* InsertWeakFromTransaction(mirror::String* s, uint32_t hash_code)
+      EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_);
+  void RemoveStrongFromTransaction(mirror::String* s, uint32_t hash_code)
+      EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_);
+  void RemoveWeakFromTransaction(mirror::String* s, uint32_t hash_code)
+      EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_);
+  friend class Transaction;
+
+  bool is_dirty_ GUARDED_BY(Locks::intern_table_lock_);
+  bool allow_new_interns_ GUARDED_BY(Locks::intern_table_lock_);
+  ConditionVariable new_intern_condition_ GUARDED_BY(Locks::intern_table_lock_);
+  Table strong_interns_ GUARDED_BY(Locks::intern_table_lock_);
+  Table weak_interns_ GUARDED_BY(Locks::intern_table_lock_);
 };
 
 }  // namespace art
diff --git a/runtime/interpreter/interpreter.cc b/runtime/interpreter/interpreter.cc
index c6faf44..a674571 100644
--- a/runtime/interpreter/interpreter.cc
+++ b/runtime/interpreter/interpreter.cc
@@ -15,6 +15,7 @@
  */
 
 #include "interpreter_common.h"
+#include <limits>
 
 namespace art {
 namespace interpreter {
@@ -23,6 +24,10 @@
 static void UnstartedRuntimeJni(Thread* self, ArtMethod* method,
                                 Object* receiver, uint32_t* args, JValue* result)
     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+  DCHECK(Runtime::Current()->IsActiveTransaction()) << "Calling native method "
+                                                    << PrettyMethod(method)
+                                                    << " in unstarted runtime should only happen"
+                                                    << " in a transaction";
   std::string name(PrettyMethod(method));
   if (name == "java.lang.ClassLoader dalvik.system.VMStack.getCallingClassLoader()") {
     result->SetL(NULL);
@@ -73,13 +78,18 @@
     jint newValue = args[4];
     byte* raw_addr = reinterpret_cast<byte*>(obj) + offset;
     volatile int32_t* address = reinterpret_cast<volatile int32_t*>(raw_addr);
+    // Check offset is 32bits to fit in MemberOffset.
+    CHECK_GE(offset, static_cast<jlong>(std::numeric_limits<int32_t>::min()));
+    CHECK_LE(offset, static_cast<jlong>(std::numeric_limits<int32_t>::max()));
+    Runtime::Current()->RecordWriteField32(obj, MemberOffset(offset), *address, true);
     // Note: android_atomic_release_cas() returns 0 on success, not failure.
     int r = android_atomic_release_cas(expectedValue, newValue, address);
     result->SetZ(r == 0);
   } else if (name == "void sun.misc.Unsafe.putObject(java.lang.Object, long, java.lang.Object)") {
     Object* obj = reinterpret_cast<Object*>(args[0]);
     Object* newValue = reinterpret_cast<Object*>(args[3]);
-    obj->SetFieldObject(MemberOffset((static_cast<uint64_t>(args[2]) << 32) | args[1]), newValue, false);
+    obj->SetFieldObject<true>(MemberOffset((static_cast<uint64_t>(args[2]) << 32) | args[1]),
+                              newValue, false);
   } else if (name == "int sun.misc.Unsafe.getArrayBaseOffsetForComponentType(java.lang.Class)") {
     mirror::Class* component = reinterpret_cast<Object*>(args[0])->AsClass();
     Primitive::Type primitive_type = component->GetPrimitiveType();
@@ -89,7 +99,11 @@
     Primitive::Type primitive_type = component->GetPrimitiveType();
     result->SetI(Primitive::ComponentSize(primitive_type));
   } else {
-    LOG(FATAL) << "Attempt to invoke native method in non-started runtime: " << name;
+    // Throw an exception so we can abort the transaction and undo every change.
+    ThrowLocation throw_location;
+    self->ThrowNewExceptionF(throw_location, "Ljava/lang/InternalError;",
+                             "Attempt to invoke native method in non-started runtime: %s",
+                             name.c_str());
   }
 }
 
@@ -293,21 +307,38 @@
   DCHECK(!shadow_frame.GetMethod()->IsAbstract());
   DCHECK(!shadow_frame.GetMethod()->IsNative());
 
+  bool transaction_active = Runtime::Current()->IsActiveTransaction();
   if (LIKELY(shadow_frame.GetMethod()->IsPreverified())) {
     // Enter the "without access check" interpreter.
     if (kInterpreterImplKind == kSwitchImpl) {
-      return ExecuteSwitchImpl<false>(self, mh, code_item, shadow_frame, result_register);
+      if (transaction_active) {
+        return ExecuteSwitchImpl<false, true>(self, mh, code_item, shadow_frame, result_register);
+      } else {
+        return ExecuteSwitchImpl<false, false>(self, mh, code_item, shadow_frame, result_register);
+      }
     } else {
       DCHECK_EQ(kInterpreterImplKind, kComputedGotoImplKind);
-      return ExecuteGotoImpl<false>(self, mh, code_item, shadow_frame, result_register);
+      if (transaction_active) {
+        return ExecuteGotoImpl<false, true>(self, mh, code_item, shadow_frame, result_register);
+      } else {
+        return ExecuteGotoImpl<false, false>(self, mh, code_item, shadow_frame, result_register);
+      }
     }
   } else {
     // Enter the "with access check" interpreter.
     if (kInterpreterImplKind == kSwitchImpl) {
-      return ExecuteSwitchImpl<true>(self, mh, code_item, shadow_frame, result_register);
+      if (transaction_active) {
+        return ExecuteSwitchImpl<true, true>(self, mh, code_item, shadow_frame, result_register);
+      } else {
+        return ExecuteSwitchImpl<true, false>(self, mh, code_item, shadow_frame, result_register);
+      }
     } else {
       DCHECK_EQ(kInterpreterImplKind, kComputedGotoImplKind);
-      return ExecuteGotoImpl<true>(self, mh, code_item, shadow_frame, result_register);
+      if (transaction_active) {
+        return ExecuteGotoImpl<true, true>(self, mh, code_item, shadow_frame, result_register);
+      } else {
+        return ExecuteGotoImpl<true, false>(self, mh, code_item, shadow_frame, result_register);
+      }
     }
   }
 }
diff --git a/runtime/interpreter/interpreter_common.cc b/runtime/interpreter/interpreter_common.cc
index 0b959fb..e37fb61 100644
--- a/runtime/interpreter/interpreter_common.cc
+++ b/runtime/interpreter/interpreter_common.cc
@@ -15,6 +15,7 @@
  */
 
 #include "interpreter_common.h"
+#include "mirror/array-inl.h"
 
 namespace art {
 namespace interpreter {
@@ -161,7 +162,7 @@
   return !self->IsExceptionPending();
 }
 
-template <bool is_range, bool do_access_check>
+template <bool is_range, bool do_access_check, bool transaction_active>
 bool DoFilledNewArray(const Instruction* inst, const ShadowFrame& shadow_frame,
                       Thread* self, JValue* result) {
   DCHECK(inst->Opcode() == Instruction::FILLED_NEW_ARRAY ||
@@ -212,9 +213,9 @@
   for (int32_t i = 0; i < length; ++i) {
     size_t src_reg = is_range ? vregC + i : arg[i];
     if (is_primitive_int_component) {
-      newArray->AsIntArray()->SetWithoutChecks(i, shadow_frame.GetVReg(src_reg));
+      newArray->AsIntArray()->SetWithoutChecks<transaction_active>(i, shadow_frame.GetVReg(src_reg));
     } else {
-      newArray->AsObjectArray<Object>()->SetWithoutChecks(i, shadow_frame.GetVRegReference(src_reg));
+      newArray->AsObjectArray<Object>()->SetWithoutChecks<transaction_active>(i, shadow_frame.GetVRegReference(src_reg));
     }
   }
 
@@ -222,6 +223,50 @@
   return true;
 }
 
+// TODO fix thread analysis: should be SHARED_LOCKS_REQUIRED(Locks::mutator_lock_).
+template<typename T>
+static void RecordArrayElementsInTransactionImpl(mirror::PrimitiveArray<T>* array, int32_t count)
+    NO_THREAD_SAFETY_ANALYSIS {
+  Runtime* runtime = Runtime::Current();
+  for (int32_t i = 0; i < count; ++i) {
+    runtime->RecordWriteArray(array, i, array->GetWithoutChecks(i));
+  }
+}
+
+void RecordArrayElementsInTransaction(mirror::Array* array, int32_t count)
+    SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+  DCHECK(Runtime::Current()->IsActiveTransaction());
+  DCHECK(array != nullptr);
+  DCHECK_LE(count, array->GetLength());
+  Primitive::Type primitive_component_type = array->GetClass()->GetComponentType()->GetPrimitiveType();
+  switch (primitive_component_type) {
+    case Primitive::kPrimBoolean:
+      RecordArrayElementsInTransactionImpl(array->AsBooleanArray(), count);
+      break;
+    case Primitive::kPrimByte:
+      RecordArrayElementsInTransactionImpl(array->AsByteArray(), count);
+      break;
+    case Primitive::kPrimChar:
+      RecordArrayElementsInTransactionImpl(array->AsCharArray(), count);
+      break;
+    case Primitive::kPrimShort:
+      RecordArrayElementsInTransactionImpl(array->AsShortArray(), count);
+      break;
+    case Primitive::kPrimInt:
+    case Primitive::kPrimFloat:
+      RecordArrayElementsInTransactionImpl(array->AsIntArray(), count);
+      break;
+    case Primitive::kPrimLong:
+    case Primitive::kPrimDouble:
+      RecordArrayElementsInTransactionImpl(array->AsLongArray(), count);
+      break;
+    default:
+      LOG(FATAL) << "Unsupported primitive type " << primitive_component_type
+                 << " in fill-array-data";
+      break;
+  }
+}
+
 static void UnstartedRuntimeInvoke(Thread* self, MethodHelper& mh,
                                    const DexFile::CodeItem* code_item, ShadowFrame* shadow_frame,
                                    JValue* result, size_t arg_offset) {
@@ -341,15 +386,19 @@
 #undef EXPLICIT_DO_CALL_TEMPLATE_DECL
 
 // Explicit DoFilledNewArray template function declarations.
-#define EXPLICIT_DO_FILLED_NEW_ARRAY_TEMPLATE_DECL(_is_range_, _check)                \
-  template SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)                                \
-  bool DoFilledNewArray<_is_range_, _check>(const Instruction* inst,                  \
-                                                     const ShadowFrame& shadow_frame, \
-                                                     Thread* self, JValue* result)
-EXPLICIT_DO_FILLED_NEW_ARRAY_TEMPLATE_DECL(false, false);
-EXPLICIT_DO_FILLED_NEW_ARRAY_TEMPLATE_DECL(false, true);
-EXPLICIT_DO_FILLED_NEW_ARRAY_TEMPLATE_DECL(true, false);
-EXPLICIT_DO_FILLED_NEW_ARRAY_TEMPLATE_DECL(true, true);
+#define EXPLICIT_DO_FILLED_NEW_ARRAY_TEMPLATE_DECL(_is_range_, _check, _transaction_active)       \
+  template SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)                                            \
+  bool DoFilledNewArray<_is_range_, _check, _transaction_active>(const Instruction* inst,         \
+                                                                 const ShadowFrame& shadow_frame, \
+                                                                 Thread* self, JValue* result)
+#define EXPLICIT_DO_FILLED_NEW_ARRAY_ALL_TEMPLATE_DECL(_transaction_active)       \
+  EXPLICIT_DO_FILLED_NEW_ARRAY_TEMPLATE_DECL(false, false, _transaction_active);  \
+  EXPLICIT_DO_FILLED_NEW_ARRAY_TEMPLATE_DECL(false, true, _transaction_active);   \
+  EXPLICIT_DO_FILLED_NEW_ARRAY_TEMPLATE_DECL(true, false, _transaction_active);   \
+  EXPLICIT_DO_FILLED_NEW_ARRAY_TEMPLATE_DECL(true, true, _transaction_active)
+EXPLICIT_DO_FILLED_NEW_ARRAY_ALL_TEMPLATE_DECL(false);
+EXPLICIT_DO_FILLED_NEW_ARRAY_ALL_TEMPLATE_DECL(true);
+#undef EXPLICIT_DO_FILLED_NEW_ARRAY_ALL_TEMPLATE_DECL
 #undef EXPLICIT_DO_FILLED_NEW_ARRAY_TEMPLATE_DECL
 
 }  // namespace interpreter
diff --git a/runtime/interpreter/interpreter_common.h b/runtime/interpreter/interpreter_common.h
index 768ca33..a03e420 100644
--- a/runtime/interpreter/interpreter_common.h
+++ b/runtime/interpreter/interpreter_common.h
@@ -65,12 +65,12 @@
 
 // External references to both interpreter implementations.
 
-template<bool do_access_check>
+template<bool do_access_check, bool transaction_active>
 extern JValue ExecuteSwitchImpl(Thread* self, MethodHelper& mh,
                                 const DexFile::CodeItem* code_item,
                                 ShadowFrame& shadow_frame, JValue result_register);
 
-template<bool do_access_check>
+template<bool do_access_check, bool transaction_active>
 extern JValue ExecuteGotoImpl(Thread* self, MethodHelper& mh,
                               const DexFile::CodeItem* code_item,
                               ShadowFrame& shadow_frame, JValue result_register);
@@ -83,6 +83,9 @@
   ref->MonitorExit(self);
 }
 
+void RecordArrayElementsInTransaction(mirror::Array* array, int32_t count)
+    SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
 // Invokes the given method. This is part of the invocation support and is used by DoInvoke and
 // DoInvokeVirtualQuick functions.
 // Returns true on success, otherwise throws an exception and returns false.
@@ -228,7 +231,7 @@
 
 // Handles iput-XXX and sput-XXX instructions.
 // Returns true on success, otherwise throws an exception and returns false.
-template<FindFieldType find_type, Primitive::Type field_type, bool do_access_check>
+template<FindFieldType find_type, Primitive::Type field_type, bool do_access_check, bool transaction_active>
 static inline bool DoFieldPut(Thread* self, const ShadowFrame& shadow_frame,
                               const Instruction* inst, uint16_t inst_data) {
   bool do_assignability_check = do_access_check;
@@ -254,22 +257,22 @@
   uint32_t vregA = is_static ? inst->VRegA_21c(inst_data) : inst->VRegA_22c(inst_data);
   switch (field_type) {
     case Primitive::kPrimBoolean:
-      f->SetBoolean(obj, shadow_frame.GetVReg(vregA));
+      f->SetBoolean<transaction_active>(obj, shadow_frame.GetVReg(vregA));
       break;
     case Primitive::kPrimByte:
-      f->SetByte(obj, shadow_frame.GetVReg(vregA));
+      f->SetByte<transaction_active>(obj, shadow_frame.GetVReg(vregA));
       break;
     case Primitive::kPrimChar:
-      f->SetChar(obj, shadow_frame.GetVReg(vregA));
+      f->SetChar<transaction_active>(obj, shadow_frame.GetVReg(vregA));
       break;
     case Primitive::kPrimShort:
-      f->SetShort(obj, shadow_frame.GetVReg(vregA));
+      f->SetShort<transaction_active>(obj, shadow_frame.GetVReg(vregA));
       break;
     case Primitive::kPrimInt:
-      f->SetInt(obj, shadow_frame.GetVReg(vregA));
+      f->SetInt<transaction_active>(obj, shadow_frame.GetVReg(vregA));
       break;
     case Primitive::kPrimLong:
-      f->SetLong(obj, shadow_frame.GetVRegLong(vregA));
+      f->SetLong<transaction_active>(obj, shadow_frame.GetVRegLong(vregA));
       break;
     case Primitive::kPrimNot: {
       Object* reg = shadow_frame.GetVRegReference(vregA);
@@ -286,7 +289,7 @@
           return false;
         }
       }
-      f->SetObj(obj, reg);
+      f->SetObj<transaction_active>(obj, reg);
       break;
     }
     default:
@@ -297,7 +300,7 @@
 
 // Handles iput-quick, iput-wide-quick and iput-object-quick instructions.
 // Returns true on success, otherwise throws an exception and returns false.
-template<Primitive::Type field_type>
+template<Primitive::Type field_type, bool transaction_active>
 static inline bool DoIPutQuick(const ShadowFrame& shadow_frame, const Instruction* inst, uint16_t inst_data) {
   Object* obj = shadow_frame.GetVRegReference(inst->VRegB_22c(inst_data));
   if (UNLIKELY(obj == nullptr)) {
@@ -311,13 +314,15 @@
   const uint32_t vregA = inst->VRegA_22c(inst_data);
   switch (field_type) {
     case Primitive::kPrimInt:
-      obj->SetField32(field_offset, shadow_frame.GetVReg(vregA), is_volatile);
+      obj->SetField32<transaction_active>(field_offset, shadow_frame.GetVReg(vregA), is_volatile);
       break;
     case Primitive::kPrimLong:
-      obj->SetField64(field_offset, shadow_frame.GetVRegLong(vregA), is_volatile);
+      obj->SetField64<transaction_active>(field_offset, shadow_frame.GetVRegLong(vregA),
+                                          is_volatile);
       break;
     case Primitive::kPrimNot:
-      obj->SetFieldObject(field_offset, shadow_frame.GetVRegReference(vregA), is_volatile);
+      obj->SetFieldObject<transaction_active>(field_offset, shadow_frame.GetVRegReference(vregA),
+                                              is_volatile);
       break;
     default:
       LOG(FATAL) << "Unreachable: " << field_type;
@@ -416,7 +421,7 @@
 
 // Handles filled-new-array and filled-new-array-range instructions.
 // Returns true on success, otherwise throws an exception and returns false.
-template <bool is_range, bool do_access_check>
+template <bool is_range, bool do_access_check, bool transaction_active>
 bool DoFilledNewArray(const Instruction* inst, const ShadowFrame& shadow_frame,
                       Thread* self, JValue* result);
 
@@ -604,14 +609,16 @@
 #undef EXPLICIT_DO_FIELD_GET_TEMPLATE_DECL
 
 // Explicitly instantiate all DoFieldPut functions.
-#define EXPLICIT_DO_FIELD_PUT_TEMPLATE_DECL(_find_type, _field_type, _do_check)                      \
+#define EXPLICIT_DO_FIELD_PUT_TEMPLATE_DECL(_find_type, _field_type, _do_check, _transaction_active)                      \
   template SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) ALWAYS_INLINE                                 \
-  bool DoFieldPut<_find_type, _field_type, _do_check>(Thread* self, const ShadowFrame& shadow_frame, \
-                                                      const Instruction* inst, uint16_t inst_data)
+  bool DoFieldPut<_find_type, _field_type, _do_check, _transaction_active>(Thread* self, const ShadowFrame& shadow_frame, \
+                                                                           const Instruction* inst, uint16_t inst_data)
 
 #define EXPLICIT_DO_FIELD_PUT_ALL_TEMPLATE_DECL(_find_type, _field_type)  \
-    EXPLICIT_DO_FIELD_PUT_TEMPLATE_DECL(_find_type, _field_type, false);  \
-    EXPLICIT_DO_FIELD_PUT_TEMPLATE_DECL(_find_type, _field_type, true);
+    EXPLICIT_DO_FIELD_PUT_TEMPLATE_DECL(_find_type, _field_type, false, false);  \
+    EXPLICIT_DO_FIELD_PUT_TEMPLATE_DECL(_find_type, _field_type, true, false);  \
+    EXPLICIT_DO_FIELD_PUT_TEMPLATE_DECL(_find_type, _field_type, false, true);  \
+    EXPLICIT_DO_FIELD_PUT_TEMPLATE_DECL(_find_type, _field_type, true, true);
 
 // iput-XXX
 EXPLICIT_DO_FIELD_PUT_ALL_TEMPLATE_DECL(InstancePrimitiveWrite, Primitive::kPrimBoolean);
@@ -657,14 +664,20 @@
 #undef EXPLICIT_DO_IGET_QUICK_TEMPLATE_DECL
 
 // Explicitly instantiate all DoIPutQuick functions.
-#define EXPLICIT_DO_IPUT_QUICK_TEMPLATE_DECL(_field_type)                                  \
-  template SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) ALWAYS_INLINE                       \
-  bool DoIPutQuick<_field_type>(const ShadowFrame& shadow_frame, const Instruction* inst,  \
-                                uint16_t inst_data)
+#define EXPLICIT_DO_IPUT_QUICK_TEMPLATE_DECL(_field_type, _transaction_active)        \
+  template SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) ALWAYS_INLINE                  \
+  bool DoIPutQuick<_field_type, _transaction_active>(const ShadowFrame& shadow_frame, \
+                                                     const Instruction* inst,         \
+                                                     uint16_t inst_data)
 
-EXPLICIT_DO_IPUT_QUICK_TEMPLATE_DECL(Primitive::kPrimInt);    // iget-quick.
-EXPLICIT_DO_IPUT_QUICK_TEMPLATE_DECL(Primitive::kPrimLong);   // iget-wide-quick.
-EXPLICIT_DO_IPUT_QUICK_TEMPLATE_DECL(Primitive::kPrimNot);    // iget-object-quick.
+#define EXPLICIT_DO_IPUT_QUICK_ALL_TEMPLATE_DECL(_field_type)   \
+  EXPLICIT_DO_IPUT_QUICK_TEMPLATE_DECL(_field_type, false);     \
+  EXPLICIT_DO_IPUT_QUICK_TEMPLATE_DECL(_field_type, true);
+
+EXPLICIT_DO_IPUT_QUICK_ALL_TEMPLATE_DECL(Primitive::kPrimInt);    // iget-quick.
+EXPLICIT_DO_IPUT_QUICK_ALL_TEMPLATE_DECL(Primitive::kPrimLong);   // iget-wide-quick.
+EXPLICIT_DO_IPUT_QUICK_ALL_TEMPLATE_DECL(Primitive::kPrimNot);    // iget-object-quick.
+#undef EXPLICIT_DO_IPUT_QUICK_ALL_TEMPLATE_DECL
 #undef EXPLICIT_DO_IPUT_QUICK_TEMPLATE_DECL
 
 }  // namespace interpreter
diff --git a/runtime/interpreter/interpreter_goto_table_impl.cc b/runtime/interpreter/interpreter_goto_table_impl.cc
index e8504b7..d0bb001 100644
--- a/runtime/interpreter/interpreter_goto_table_impl.cc
+++ b/runtime/interpreter/interpreter_goto_table_impl.cc
@@ -109,7 +109,7 @@
  * ---------------------+---------------+
  *
  */
-template<bool do_access_check>
+template<bool do_access_check, bool transaction_active>
 JValue ExecuteGotoImpl(Thread* self, MethodHelper& mh, const DexFile::CodeItem* code_item,
                        ShadowFrame& shadow_frame, JValue result_register) {
   // Define handler tables:
@@ -536,15 +536,17 @@
   HANDLE_INSTRUCTION_END();
 
   HANDLE_INSTRUCTION_START(FILLED_NEW_ARRAY) {
-    bool success = DoFilledNewArray<false, do_access_check>(inst, shadow_frame,
-                                                            self, &result_register);
+    bool success =
+        DoFilledNewArray<false, do_access_check, transaction_active>(inst, shadow_frame,
+                                                                     self, &result_register);
     POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, 3);
   }
   HANDLE_INSTRUCTION_END();
 
   HANDLE_INSTRUCTION_START(FILLED_NEW_ARRAY_RANGE) {
-    bool success = DoFilledNewArray<true, do_access_check>(inst, shadow_frame,
-                                                           self, &result_register);
+    bool success =
+        DoFilledNewArray<true, do_access_check, transaction_active>(inst, shadow_frame,
+                                                                    self, &result_register);
     POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, 3);
   }
   HANDLE_INSTRUCTION_END();
@@ -567,6 +569,9 @@
                                  array->GetLength(), payload->element_count);
         HANDLE_PENDING_EXCEPTION();
       } else {
+        if (transaction_active) {
+          RecordArrayElementsInTransaction(array, payload->element_count);
+        }
         uint32_t size_in_bytes = payload->element_count * payload->element_width;
         memcpy(array->GetRawData(payload->element_width, 0), payload->data, size_in_bytes);
         ADVANCE(3);
@@ -1060,7 +1065,7 @@
       int32_t index = shadow_frame.GetVReg(inst->VRegC_23x());
       BooleanArray* array = a->AsBooleanArray();
       if (LIKELY(array->CheckIsValidIndex(index))) {
-        array->SetWithoutChecks(index, val);
+        array->SetWithoutChecks<transaction_active>(index, val);
         ADVANCE(2);
       } else {
         HANDLE_PENDING_EXCEPTION();
@@ -1079,7 +1084,7 @@
       int32_t index = shadow_frame.GetVReg(inst->VRegC_23x());
       ByteArray* array = a->AsByteArray();
       if (LIKELY(array->CheckIsValidIndex(index))) {
-        array->SetWithoutChecks(index, val);
+        array->SetWithoutChecks<transaction_active>(index, val);
         ADVANCE(2);
       } else {
         HANDLE_PENDING_EXCEPTION();
@@ -1098,7 +1103,7 @@
       int32_t index = shadow_frame.GetVReg(inst->VRegC_23x());
       CharArray* array = a->AsCharArray();
       if (LIKELY(array->CheckIsValidIndex(index))) {
-        array->SetWithoutChecks(index, val);
+        array->SetWithoutChecks<transaction_active>(index, val);
         ADVANCE(2);
       } else {
         HANDLE_PENDING_EXCEPTION();
@@ -1117,7 +1122,7 @@
       int32_t index = shadow_frame.GetVReg(inst->VRegC_23x());
       ShortArray* array = a->AsShortArray();
       if (LIKELY(array->CheckIsValidIndex(index))) {
-        array->SetWithoutChecks(index, val);
+        array->SetWithoutChecks<transaction_active>(index, val);
         ADVANCE(2);
       } else {
         HANDLE_PENDING_EXCEPTION();
@@ -1136,7 +1141,7 @@
       int32_t index = shadow_frame.GetVReg(inst->VRegC_23x());
       IntArray* array = a->AsIntArray();
       if (LIKELY(array->CheckIsValidIndex(index))) {
-        array->SetWithoutChecks(index, val);
+        array->SetWithoutChecks<transaction_active>(index, val);
         ADVANCE(2);
       } else {
         HANDLE_PENDING_EXCEPTION();
@@ -1155,7 +1160,7 @@
       int32_t index = shadow_frame.GetVReg(inst->VRegC_23x());
       LongArray* array = a->AsLongArray();
       if (LIKELY(array->CheckIsValidIndex(index))) {
-        array->SetWithoutChecks(index, val);
+        array->SetWithoutChecks<transaction_active>(index, val);
         ADVANCE(2);
       } else {
         HANDLE_PENDING_EXCEPTION();
@@ -1174,7 +1179,7 @@
       Object* val = shadow_frame.GetVRegReference(inst->VRegA_23x(inst_data));
       ObjectArray<Object>* array = a->AsObjectArray<Object>();
       if (LIKELY(array->CheckIsValidIndex(index) && array->CheckAssignable(val))) {
-        array->SetWithoutChecks(index, val);
+        array->SetWithoutChecks<transaction_active>(index, val);
         ADVANCE(2);
       } else {
         HANDLE_PENDING_EXCEPTION();
@@ -1286,103 +1291,103 @@
   HANDLE_INSTRUCTION_END();
 
   HANDLE_INSTRUCTION_START(IPUT_BOOLEAN) {
-    bool success = DoFieldPut<InstancePrimitiveWrite, Primitive::kPrimBoolean, do_access_check>(self, shadow_frame, inst, inst_data);
+    bool success = DoFieldPut<InstancePrimitiveWrite, Primitive::kPrimBoolean, do_access_check, transaction_active>(self, shadow_frame, inst, inst_data);
     POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, 2);
   }
   HANDLE_INSTRUCTION_END();
 
   HANDLE_INSTRUCTION_START(IPUT_BYTE) {
-    bool success = DoFieldPut<InstancePrimitiveWrite, Primitive::kPrimByte, do_access_check>(self, shadow_frame, inst, inst_data);
+    bool success = DoFieldPut<InstancePrimitiveWrite, Primitive::kPrimByte, do_access_check, transaction_active>(self, shadow_frame, inst, inst_data);
     POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, 2);
   }
   HANDLE_INSTRUCTION_END();
 
   HANDLE_INSTRUCTION_START(IPUT_CHAR) {
-    bool success = DoFieldPut<InstancePrimitiveWrite, Primitive::kPrimChar, do_access_check>(self, shadow_frame, inst, inst_data);
+    bool success = DoFieldPut<InstancePrimitiveWrite, Primitive::kPrimChar, do_access_check, transaction_active>(self, shadow_frame, inst, inst_data);
     POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, 2);
   }
   HANDLE_INSTRUCTION_END();
 
   HANDLE_INSTRUCTION_START(IPUT_SHORT) {
-    bool success = DoFieldPut<InstancePrimitiveWrite, Primitive::kPrimShort, do_access_check>(self, shadow_frame, inst, inst_data);
+    bool success = DoFieldPut<InstancePrimitiveWrite, Primitive::kPrimShort, do_access_check, transaction_active>(self, shadow_frame, inst, inst_data);
     POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, 2);
   }
   HANDLE_INSTRUCTION_END();
 
   HANDLE_INSTRUCTION_START(IPUT) {
-    bool success = DoFieldPut<InstancePrimitiveWrite, Primitive::kPrimInt, do_access_check>(self, shadow_frame, inst, inst_data);
+    bool success = DoFieldPut<InstancePrimitiveWrite, Primitive::kPrimInt, do_access_check, transaction_active>(self, shadow_frame, inst, inst_data);
     POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, 2);
   }
   HANDLE_INSTRUCTION_END();
 
   HANDLE_INSTRUCTION_START(IPUT_WIDE) {
-    bool success = DoFieldPut<InstancePrimitiveWrite, Primitive::kPrimLong, do_access_check>(self, shadow_frame, inst, inst_data);
+    bool success = DoFieldPut<InstancePrimitiveWrite, Primitive::kPrimLong, do_access_check, transaction_active>(self, shadow_frame, inst, inst_data);
     POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, 2);
   }
   HANDLE_INSTRUCTION_END();
 
   HANDLE_INSTRUCTION_START(IPUT_OBJECT) {
-    bool success = DoFieldPut<InstanceObjectWrite, Primitive::kPrimNot, do_access_check>(self, shadow_frame, inst, inst_data);
+    bool success = DoFieldPut<InstanceObjectWrite, Primitive::kPrimNot, do_access_check, transaction_active>(self, shadow_frame, inst, inst_data);
     POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, 2);
   }
   HANDLE_INSTRUCTION_END();
 
   HANDLE_INSTRUCTION_START(IPUT_QUICK) {
-    bool success = DoIPutQuick<Primitive::kPrimInt>(shadow_frame, inst, inst_data);
+    bool success = DoIPutQuick<Primitive::kPrimInt, transaction_active>(shadow_frame, inst, inst_data);
     POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, 2);
   }
   HANDLE_INSTRUCTION_END();
 
   HANDLE_INSTRUCTION_START(IPUT_WIDE_QUICK) {
-    bool success = DoIPutQuick<Primitive::kPrimLong>(shadow_frame, inst, inst_data);
+    bool success = DoIPutQuick<Primitive::kPrimLong, transaction_active>(shadow_frame, inst, inst_data);
     POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, 2);
   }
   HANDLE_INSTRUCTION_END();
 
   HANDLE_INSTRUCTION_START(IPUT_OBJECT_QUICK) {
-    bool success = DoIPutQuick<Primitive::kPrimNot>(shadow_frame, inst, inst_data);
+    bool success = DoIPutQuick<Primitive::kPrimNot, transaction_active>(shadow_frame, inst, inst_data);
     POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, 2);
   }
   HANDLE_INSTRUCTION_END();
 
   HANDLE_INSTRUCTION_START(SPUT_BOOLEAN) {
-    bool success = DoFieldPut<StaticPrimitiveWrite, Primitive::kPrimBoolean, do_access_check>(self, shadow_frame, inst, inst_data);
+    bool success = DoFieldPut<StaticPrimitiveWrite, Primitive::kPrimBoolean, do_access_check, transaction_active>(self, shadow_frame, inst, inst_data);
     POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, 2);
   }
   HANDLE_INSTRUCTION_END();
 
   HANDLE_INSTRUCTION_START(SPUT_BYTE) {
-    bool success = DoFieldPut<StaticPrimitiveWrite, Primitive::kPrimByte, do_access_check>(self, shadow_frame, inst, inst_data);
+    bool success = DoFieldPut<StaticPrimitiveWrite, Primitive::kPrimByte, do_access_check, transaction_active>(self, shadow_frame, inst, inst_data);
     POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, 2);
   }
   HANDLE_INSTRUCTION_END();
 
   HANDLE_INSTRUCTION_START(SPUT_CHAR) {
-    bool success = DoFieldPut<StaticPrimitiveWrite, Primitive::kPrimChar, do_access_check>(self, shadow_frame, inst, inst_data);
+    bool success = DoFieldPut<StaticPrimitiveWrite, Primitive::kPrimChar, do_access_check, transaction_active>(self, shadow_frame, inst, inst_data);
     POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, 2);
   }
   HANDLE_INSTRUCTION_END();
 
   HANDLE_INSTRUCTION_START(SPUT_SHORT) {
-    bool success = DoFieldPut<StaticPrimitiveWrite, Primitive::kPrimShort, do_access_check>(self, shadow_frame, inst, inst_data);
+    bool success = DoFieldPut<StaticPrimitiveWrite, Primitive::kPrimShort, do_access_check, transaction_active>(self, shadow_frame, inst, inst_data);
     POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, 2);
   }
   HANDLE_INSTRUCTION_END();
 
   HANDLE_INSTRUCTION_START(SPUT) {
-    bool success = DoFieldPut<StaticPrimitiveWrite, Primitive::kPrimInt, do_access_check>(self, shadow_frame, inst, inst_data);
+    bool success = DoFieldPut<StaticPrimitiveWrite, Primitive::kPrimInt, do_access_check, transaction_active>(self, shadow_frame, inst, inst_data);
     POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, 2);
   }
   HANDLE_INSTRUCTION_END();
 
   HANDLE_INSTRUCTION_START(SPUT_WIDE) {
-    bool success = DoFieldPut<StaticPrimitiveWrite, Primitive::kPrimLong, do_access_check>(self, shadow_frame, inst, inst_data);
+    bool success = DoFieldPut<StaticPrimitiveWrite, Primitive::kPrimLong, do_access_check, transaction_active>(self, shadow_frame, inst, inst_data);
     POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, 2);
   }
   HANDLE_INSTRUCTION_END();
 
   HANDLE_INSTRUCTION_START(SPUT_OBJECT) {
-    bool success = DoFieldPut<StaticObjectWrite, Primitive::kPrimNot, do_access_check>(self, shadow_frame, inst, inst_data);
+    bool success = DoFieldPut<StaticObjectWrite, Primitive::kPrimNot, do_access_check, transaction_active>(self, shadow_frame, inst, inst_data);
     POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, 2);
   }
   HANDLE_INSTRUCTION_END();
@@ -2390,13 +2395,21 @@
 
 // Explicit definitions of ExecuteGotoImpl.
 template SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) HOT_ATTR
-JValue ExecuteGotoImpl<true>(Thread* self, MethodHelper& mh,
-                             const DexFile::CodeItem* code_item,
-                             ShadowFrame& shadow_frame, JValue result_register);
+JValue ExecuteGotoImpl<true, false>(Thread* self, MethodHelper& mh,
+                                    const DexFile::CodeItem* code_item,
+                                    ShadowFrame& shadow_frame, JValue result_register);
 template SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) HOT_ATTR
-JValue ExecuteGotoImpl<false>(Thread* self, MethodHelper& mh,
-                              const DexFile::CodeItem* code_item,
-                              ShadowFrame& shadow_frame, JValue result_register);
+JValue ExecuteGotoImpl<false, false>(Thread* self, MethodHelper& mh,
+                                     const DexFile::CodeItem* code_item,
+                                     ShadowFrame& shadow_frame, JValue result_register);
+template SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
+JValue ExecuteGotoImpl<true, true>(Thread* self, MethodHelper& mh,
+                                    const DexFile::CodeItem* code_item,
+                                    ShadowFrame& shadow_frame, JValue result_register);
+template SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
+JValue ExecuteGotoImpl<false, true>(Thread* self, MethodHelper& mh,
+                                     const DexFile::CodeItem* code_item,
+                                     ShadowFrame& shadow_frame, JValue result_register);
 
 }  // namespace interpreter
 }  // namespace art
diff --git a/runtime/interpreter/interpreter_switch_impl.cc b/runtime/interpreter/interpreter_switch_impl.cc
index e5d15b1..abee1db 100644
--- a/runtime/interpreter/interpreter_switch_impl.cc
+++ b/runtime/interpreter/interpreter_switch_impl.cc
@@ -50,7 +50,7 @@
 // Code to run before each dex instruction.
 #define PREAMBLE()
 
-template<bool do_access_check>
+template<bool do_access_check, bool transaction_active>
 JValue ExecuteSwitchImpl(Thread* self, MethodHelper& mh, const DexFile::CodeItem* code_item,
                                 ShadowFrame& shadow_frame, JValue result_register) {
   bool do_assignability_check = do_access_check;
@@ -449,15 +449,17 @@
       }
       case Instruction::FILLED_NEW_ARRAY: {
         PREAMBLE();
-        bool success = DoFilledNewArray<false, do_access_check>(inst, shadow_frame,
-                                                                self, &result_register);
+        bool success =
+            DoFilledNewArray<false, do_access_check, transaction_active>(inst, shadow_frame, self,
+                                                                         &result_register);
         POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, Next_3xx);
         break;
       }
       case Instruction::FILLED_NEW_ARRAY_RANGE: {
         PREAMBLE();
-        bool success = DoFilledNewArray<true, do_access_check>(inst, shadow_frame,
-                                                               self, &result_register);
+        bool success =
+            DoFilledNewArray<true, do_access_check, transaction_active>(inst, shadow_frame,
+                                                                        self, &result_register);
         POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, Next_3xx);
         break;
       }
@@ -482,6 +484,9 @@
           HANDLE_PENDING_EXCEPTION();
           break;
         }
+        if (transaction_active) {
+          RecordArrayElementsInTransaction(array, payload->element_count);
+        }
         uint32_t size_in_bytes = payload->element_count * payload->element_width;
         memcpy(array->GetRawData(payload->element_width, 0), payload->data, size_in_bytes);
         inst = inst->Next_3xx();
@@ -958,7 +963,7 @@
         int32_t index = shadow_frame.GetVReg(inst->VRegC_23x());
         BooleanArray* array = a->AsBooleanArray();
         if (LIKELY(array->CheckIsValidIndex(index))) {
-          array->SetWithoutChecks(index, val);
+          array->SetWithoutChecks<transaction_active>(index, val);
           inst = inst->Next_2xx();
         } else {
           HANDLE_PENDING_EXCEPTION();
@@ -977,7 +982,7 @@
         int32_t index = shadow_frame.GetVReg(inst->VRegC_23x());
         ByteArray* array = a->AsByteArray();
         if (LIKELY(array->CheckIsValidIndex(index))) {
-          array->SetWithoutChecks(index, val);
+          array->SetWithoutChecks<transaction_active>(index, val);
           inst = inst->Next_2xx();
         } else {
           HANDLE_PENDING_EXCEPTION();
@@ -996,7 +1001,7 @@
         int32_t index = shadow_frame.GetVReg(inst->VRegC_23x());
         CharArray* array = a->AsCharArray();
         if (LIKELY(array->CheckIsValidIndex(index))) {
-          array->SetWithoutChecks(index, val);
+          array->SetWithoutChecks<transaction_active>(index, val);
           inst = inst->Next_2xx();
         } else {
           HANDLE_PENDING_EXCEPTION();
@@ -1015,7 +1020,7 @@
         int32_t index = shadow_frame.GetVReg(inst->VRegC_23x());
         ShortArray* array = a->AsShortArray();
         if (LIKELY(array->CheckIsValidIndex(index))) {
-          array->SetWithoutChecks(index, val);
+          array->SetWithoutChecks<transaction_active>(index, val);
           inst = inst->Next_2xx();
         } else {
           HANDLE_PENDING_EXCEPTION();
@@ -1034,7 +1039,7 @@
         int32_t index = shadow_frame.GetVReg(inst->VRegC_23x());
         IntArray* array = a->AsIntArray();
         if (LIKELY(array->CheckIsValidIndex(index))) {
-          array->SetWithoutChecks(index, val);
+          array->SetWithoutChecks<transaction_active>(index, val);
           inst = inst->Next_2xx();
         } else {
           HANDLE_PENDING_EXCEPTION();
@@ -1053,7 +1058,7 @@
         int32_t index = shadow_frame.GetVReg(inst->VRegC_23x());
         LongArray* array = a->AsLongArray();
         if (LIKELY(array->CheckIsValidIndex(index))) {
-          array->SetWithoutChecks(index, val);
+          array->SetWithoutChecks<transaction_active>(index, val);
           inst = inst->Next_2xx();
         } else {
           HANDLE_PENDING_EXCEPTION();
@@ -1072,7 +1077,7 @@
         Object* val = shadow_frame.GetVRegReference(inst->VRegA_23x(inst_data));
         ObjectArray<Object>* array = a->AsObjectArray<Object>();
         if (LIKELY(array->CheckIsValidIndex(index) && array->CheckAssignable(val))) {
-          array->SetWithoutChecks(index, val);
+          array->SetWithoutChecks<transaction_active>(index, val);
           inst = inst->Next_2xx();
         } else {
           HANDLE_PENDING_EXCEPTION();
@@ -1183,103 +1188,103 @@
       }
       case Instruction::IPUT_BOOLEAN: {
         PREAMBLE();
-        bool success = DoFieldPut<InstancePrimitiveWrite, Primitive::kPrimBoolean, do_access_check>(self, shadow_frame, inst, inst_data);
+        bool success = DoFieldPut<InstancePrimitiveWrite, Primitive::kPrimBoolean, do_access_check, transaction_active>(self, shadow_frame, inst, inst_data);
         POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, Next_2xx);
         break;
       }
       case Instruction::IPUT_BYTE: {
         PREAMBLE();
-        bool success = DoFieldPut<InstancePrimitiveWrite, Primitive::kPrimByte, do_access_check>(self, shadow_frame, inst, inst_data);
+        bool success = DoFieldPut<InstancePrimitiveWrite, Primitive::kPrimByte, do_access_check, transaction_active>(self, shadow_frame, inst, inst_data);
         POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, Next_2xx);
         break;
       }
       case Instruction::IPUT_CHAR: {
         PREAMBLE();
-        bool success = DoFieldPut<InstancePrimitiveWrite, Primitive::kPrimChar, do_access_check>(self, shadow_frame, inst, inst_data);
+        bool success = DoFieldPut<InstancePrimitiveWrite, Primitive::kPrimChar, do_access_check, transaction_active>(self, shadow_frame, inst, inst_data);
         POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, Next_2xx);
         break;
       }
       case Instruction::IPUT_SHORT: {
         PREAMBLE();
-        bool success = DoFieldPut<InstancePrimitiveWrite, Primitive::kPrimShort, do_access_check>(self, shadow_frame, inst, inst_data);
+        bool success = DoFieldPut<InstancePrimitiveWrite, Primitive::kPrimShort, do_access_check, transaction_active>(self, shadow_frame, inst, inst_data);
         POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, Next_2xx);
         break;
       }
       case Instruction::IPUT: {
         PREAMBLE();
-        bool success = DoFieldPut<InstancePrimitiveWrite, Primitive::kPrimInt, do_access_check>(self, shadow_frame, inst, inst_data);
+        bool success = DoFieldPut<InstancePrimitiveWrite, Primitive::kPrimInt, do_access_check, transaction_active>(self, shadow_frame, inst, inst_data);
         POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, Next_2xx);
         break;
       }
       case Instruction::IPUT_WIDE: {
         PREAMBLE();
-        bool success = DoFieldPut<InstancePrimitiveWrite, Primitive::kPrimLong, do_access_check>(self, shadow_frame, inst, inst_data);
+        bool success = DoFieldPut<InstancePrimitiveWrite, Primitive::kPrimLong, do_access_check, transaction_active>(self, shadow_frame, inst, inst_data);
         POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, Next_2xx);
         break;
       }
       case Instruction::IPUT_OBJECT: {
         PREAMBLE();
-        bool success = DoFieldPut<InstanceObjectWrite, Primitive::kPrimNot, do_access_check>(self, shadow_frame, inst, inst_data);
+        bool success = DoFieldPut<InstanceObjectWrite, Primitive::kPrimNot, do_access_check, transaction_active>(self, shadow_frame, inst, inst_data);
         POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, Next_2xx);
         break;
       }
       case Instruction::IPUT_QUICK: {
         PREAMBLE();
-        bool success = DoIPutQuick<Primitive::kPrimInt>(shadow_frame, inst, inst_data);
+        bool success = DoIPutQuick<Primitive::kPrimInt, transaction_active>(shadow_frame, inst, inst_data);
         POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, Next_2xx);
         break;
       }
       case Instruction::IPUT_WIDE_QUICK: {
         PREAMBLE();
-        bool success = DoIPutQuick<Primitive::kPrimLong>(shadow_frame, inst, inst_data);
+        bool success = DoIPutQuick<Primitive::kPrimLong, transaction_active>(shadow_frame, inst, inst_data);
         POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, Next_2xx);
         break;
       }
       case Instruction::IPUT_OBJECT_QUICK: {
         PREAMBLE();
-        bool success = DoIPutQuick<Primitive::kPrimNot>(shadow_frame, inst, inst_data);
+        bool success = DoIPutQuick<Primitive::kPrimNot, transaction_active>(shadow_frame, inst, inst_data);
         POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, Next_2xx);
         break;
       }
       case Instruction::SPUT_BOOLEAN: {
         PREAMBLE();
-        bool success = DoFieldPut<StaticPrimitiveWrite, Primitive::kPrimBoolean, do_access_check>(self, shadow_frame, inst, inst_data);
+        bool success = DoFieldPut<StaticPrimitiveWrite, Primitive::kPrimBoolean, do_access_check, transaction_active>(self, shadow_frame, inst, inst_data);
         POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, Next_2xx);
         break;
       }
       case Instruction::SPUT_BYTE: {
         PREAMBLE();
-        bool success = DoFieldPut<StaticPrimitiveWrite, Primitive::kPrimByte, do_access_check>(self, shadow_frame, inst, inst_data);
+        bool success = DoFieldPut<StaticPrimitiveWrite, Primitive::kPrimByte, do_access_check, transaction_active>(self, shadow_frame, inst, inst_data);
         POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, Next_2xx);
         break;
       }
       case Instruction::SPUT_CHAR: {
         PREAMBLE();
-        bool success = DoFieldPut<StaticPrimitiveWrite, Primitive::kPrimChar, do_access_check>(self, shadow_frame, inst, inst_data);
+        bool success = DoFieldPut<StaticPrimitiveWrite, Primitive::kPrimChar, do_access_check, transaction_active>(self, shadow_frame, inst, inst_data);
         POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, Next_2xx);
         break;
       }
       case Instruction::SPUT_SHORT: {
         PREAMBLE();
-        bool success = DoFieldPut<StaticPrimitiveWrite, Primitive::kPrimShort, do_access_check>(self, shadow_frame, inst, inst_data);
+        bool success = DoFieldPut<StaticPrimitiveWrite, Primitive::kPrimShort, do_access_check, transaction_active>(self, shadow_frame, inst, inst_data);
         POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, Next_2xx);
         break;
       }
       case Instruction::SPUT: {
         PREAMBLE();
-        bool success = DoFieldPut<StaticPrimitiveWrite, Primitive::kPrimInt, do_access_check>(self, shadow_frame, inst, inst_data);
+        bool success = DoFieldPut<StaticPrimitiveWrite, Primitive::kPrimInt, do_access_check, transaction_active>(self, shadow_frame, inst, inst_data);
         POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, Next_2xx);
         break;
       }
       case Instruction::SPUT_WIDE: {
         PREAMBLE();
-        bool success = DoFieldPut<StaticPrimitiveWrite, Primitive::kPrimLong, do_access_check>(self, shadow_frame, inst, inst_data);
+        bool success = DoFieldPut<StaticPrimitiveWrite, Primitive::kPrimLong, do_access_check, transaction_active>(self, shadow_frame, inst, inst_data);
         POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, Next_2xx);
         break;
       }
       case Instruction::SPUT_OBJECT: {
         PREAMBLE();
-        bool success = DoFieldPut<StaticObjectWrite, Primitive::kPrimNot, do_access_check>(self, shadow_frame, inst, inst_data);
+        bool success = DoFieldPut<StaticObjectWrite, Primitive::kPrimNot, do_access_check, transaction_active>(self, shadow_frame, inst, inst_data);
         POSSIBLY_HANDLE_PENDING_EXCEPTION(!success, Next_2xx);
         break;
       }
@@ -2137,13 +2142,21 @@
 
 // Explicit definitions of ExecuteSwitchImpl.
 template SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) HOT_ATTR
-JValue ExecuteSwitchImpl<true>(Thread* self, MethodHelper& mh,
-                               const DexFile::CodeItem* code_item,
-                               ShadowFrame& shadow_frame, JValue result_register);
+JValue ExecuteSwitchImpl<true, false>(Thread* self, MethodHelper& mh,
+                                      const DexFile::CodeItem* code_item,
+                                      ShadowFrame& shadow_frame, JValue result_register);
 template SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) HOT_ATTR
-JValue ExecuteSwitchImpl<false>(Thread* self, MethodHelper& mh,
-                                const DexFile::CodeItem* code_item,
-                                ShadowFrame& shadow_frame, JValue result_register);
+JValue ExecuteSwitchImpl<false, false>(Thread* self, MethodHelper& mh,
+                                       const DexFile::CodeItem* code_item,
+                                       ShadowFrame& shadow_frame, JValue result_register);
+template SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
+JValue ExecuteSwitchImpl<true, true>(Thread* self, MethodHelper& mh,
+                                     const DexFile::CodeItem* code_item,
+                                     ShadowFrame& shadow_frame, JValue result_register);
+template SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
+JValue ExecuteSwitchImpl<false, true>(Thread* self, MethodHelper& mh,
+                                      const DexFile::CodeItem* code_item,
+                                      ShadowFrame& shadow_frame, JValue result_register);
 
 }  // namespace interpreter
 }  // namespace art
diff --git a/runtime/jni_internal.cc b/runtime/jni_internal.cc
index f9bcc71..876de05 100644
--- a/runtime/jni_internal.cc
+++ b/runtime/jni_internal.cc
@@ -1551,7 +1551,7 @@
     mirror::Object* o = soa.Decode<mirror::Object*>(java_object);
     mirror::Object* v = soa.Decode<mirror::Object*>(java_value);
     mirror::ArtField* f = soa.DecodeField(fid);
-    f->SetObject(o, v);
+    f->SetObject<false>(o, v);
   }
 
   static void SetStaticObjectField(JNIEnv* env, jclass, jfieldID fid, jobject java_value) {
@@ -1559,7 +1559,7 @@
     ScopedObjectAccess soa(env);
     mirror::Object* v = soa.Decode<mirror::Object*>(java_value);
     mirror::ArtField* f = soa.DecodeField(fid);
-    f->SetObject(f->GetDeclaringClass(), v);
+    f->SetObject<false>(f->GetDeclaringClass(), v);
   }
 
 #define GET_PRIMITIVE_FIELD(fn, instance) \
@@ -1582,13 +1582,13 @@
   ScopedObjectAccess soa(env); \
   mirror::Object* o = soa.Decode<mirror::Object*>(instance); \
   mirror::ArtField* f = soa.DecodeField(fid); \
-  f->Set ##fn(o, value)
+  f->Set ##fn <false>(o, value)
 
 #define SET_STATIC_PRIMITIVE_FIELD(fn, value) \
   CHECK_NON_NULL_ARGUMENT(SetStatic #fn Field, fid); \
   ScopedObjectAccess soa(env); \
   mirror::ArtField* f = soa.DecodeField(fid); \
-  f->Set ##fn(f->GetDeclaringClass(), value)
+  f->Set ##fn <false>(f->GetDeclaringClass(), value)
 
   static jboolean GetBooleanField(JNIEnv* env, jobject obj, jfieldID fid) {
     GET_PRIMITIVE_FIELD(Boolean, obj);
@@ -2085,7 +2085,7 @@
     mirror::ObjectArray<mirror::Object>* array =
         soa.Decode<mirror::ObjectArray<mirror::Object>*>(java_array);
     mirror::Object* value = soa.Decode<mirror::Object*>(java_value);
-    array->Set(index, value);
+    array->Set<false>(index, value);
   }
 
   static jbooleanArray NewBooleanArray(JNIEnv* env, jsize length) {
@@ -2166,7 +2166,7 @@
 
         } else {
           for (jsize i = 0; i < length; ++i) {
-            result->SetWithoutChecks(i, initial_object);
+            result->SetWithoutChecks<false>(i, initial_object);
           }
         }
       }
diff --git a/runtime/locks.cc b/runtime/locks.cc
index d08206a..246e339 100644
--- a/runtime/locks.cc
+++ b/runtime/locks.cc
@@ -33,6 +33,7 @@
 Mutex* Locks::trace_lock_ = NULL;
 Mutex* Locks::profiler_lock_ = NULL;
 Mutex* Locks::unexpected_signal_lock_ = NULL;
+Mutex* Locks::intern_table_lock_ = NULL;
 
 void Locks::Init() {
   if (logging_lock_ != NULL) {
@@ -49,6 +50,7 @@
     DCHECK(trace_lock_ != NULL);
     DCHECK(profiler_lock_ != NULL);
     DCHECK(unexpected_signal_lock_ != NULL);
+    DCHECK(intern_table_lock_ != NULL);
   } else {
     logging_lock_ = new Mutex("logging lock", kLoggingLock, true);
     abort_lock_ = new Mutex("abort lock", kAbortLock, true);
@@ -76,6 +78,8 @@
     profiler_lock_ = new Mutex("profiler lock", kProfilerLock);
     DCHECK(unexpected_signal_lock_ == NULL);
     unexpected_signal_lock_ = new Mutex("unexpected signal lock", kUnexpectedSignalLock, true);
+    DCHECK(intern_table_lock_ == NULL);
+    intern_table_lock_ = new Mutex("InternTable lock", kInternTableLock);
   }
 }
 
diff --git a/runtime/locks.h b/runtime/locks.h
index d4fbd91..2f9810d 100644
--- a/runtime/locks.h
+++ b/runtime/locks.h
@@ -44,6 +44,8 @@
   kDexFileMethodInlinerLock,
   kDexFileToMethodInlinerMapLock,
   kMarkSweepMarkStackLock,
+  kTransactionLogLock,
+  kInternTableLock,
   kDefaultMutexLevel,
   kMarkSweepLargeObjectLock,
   kPinTableLock,
@@ -163,6 +165,9 @@
   // doesn't try to hold a higher level Mutex.
   #define DEFAULT_MUTEX_ACQUIRED_AFTER ACQUIRED_AFTER(classlinker_classes_lock_)
 
+  // Guards intern table.
+  static Mutex* intern_table_lock_ ACQUIRED_AFTER(classlinker_classes_lock_);
+
   // Have an exclusive aborting thread.
   static Mutex* abort_lock_ ACQUIRED_AFTER(classlinker_classes_lock_);
 
diff --git a/runtime/mirror/array.cc b/runtime/mirror/array.cc
index c23234e..2180857 100644
--- a/runtime/mirror/array.cc
+++ b/runtime/mirror/array.cc
@@ -60,7 +60,8 @@
         CHECK(self->IsExceptionPending());
         return nullptr;
       }
-      new_array->AsObjectArray<Array>()->Set(i, sub_array);
+      // Use non-transactional mode without check.
+      new_array->AsObjectArray<Array>()->Set<false, false>(i, sub_array);
     }
   }
   return new_array.get();
diff --git a/runtime/mirror/array.h b/runtime/mirror/array.h
index 2e123ef..7555975 100644
--- a/runtime/mirror/array.h
+++ b/runtime/mirror/array.h
@@ -20,6 +20,7 @@
 #include "object.h"
 #include "object_callbacks.h"
 #include "gc/heap.h"
+#include "runtime.h"
 #include "thread.h"
 
 namespace art {
@@ -60,7 +61,9 @@
 
   void SetLength(int32_t length) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     CHECK_GE(length, 0);
-    SetField32(OFFSET_OF_OBJECT_MEMBER(Array, length_), length, false, false);
+    // We use non transactional version since we can't undo this write. We also disable checking
+    // since it would fail during a transaction.
+    SetField32<false, false>(OFFSET_OF_OBJECT_MEMBER(Array, length_), length, false, false);
   }
 
   static MemberOffset LengthOffset() {
@@ -144,14 +147,34 @@
   }
 
   void Set(int32_t i, T value) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+    if (Runtime::Current()->IsActiveTransaction()) {
+      Set<true>(i, value);
+    } else {
+      Set<false>(i, value);
+    }
+  }
+
+  // TODO fix thread safety analysis broken by the use of template. This should be
+  // SHARED_LOCKS_REQUIRED(Locks::mutator_lock_).
+  template<bool kTransactionActive, bool kCheckTransaction = true>
+  void Set(int32_t i, T value) NO_THREAD_SAFETY_ANALYSIS {
     if (LIKELY(CheckIsValidIndex(i))) {
-      SetWithoutChecks(i, value);
+      SetWithoutChecks<kTransactionActive, kCheckTransaction>(i, value);
     } else {
       DCHECK(Thread::Current()->IsExceptionPending());
     }
   }
 
-  void SetWithoutChecks(int32_t i, T value) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+  // TODO fix thread safety analysis broken by the use of template. This should be
+  // SHARED_LOCKS_REQUIRED(Locks::mutator_lock_).
+  template<bool kTransactionActive, bool kCheckTransaction = true>
+  void SetWithoutChecks(int32_t i, T value) NO_THREAD_SAFETY_ANALYSIS {
+    if (kCheckTransaction) {
+      DCHECK_EQ(kTransactionActive, Runtime::Current()->IsActiveTransaction());
+    }
+    if (kTransactionActive) {
+      Runtime::Current()->RecordWriteArray(this, i, GetWithoutChecks(i));
+    }
     DCHECK(CheckIsValidIndex(i));
     GetData()[i] = value;
   }
diff --git a/runtime/mirror/art_field-inl.h b/runtime/mirror/art_field-inl.h
index 530226b..6253edd 100644
--- a/runtime/mirror/art_field-inl.h
+++ b/runtime/mirror/art_field-inl.h
@@ -37,7 +37,8 @@
 }
 
 inline void ArtField::SetDeclaringClass(Class *new_declaring_class) {
-  SetFieldObject(OFFSET_OF_OBJECT_MEMBER(ArtField, declaring_class_), new_declaring_class, false);
+  SetFieldObject<false>(OFFSET_OF_OBJECT_MEMBER(ArtField, declaring_class_),
+                        new_declaring_class, false);
 }
 
 inline uint32_t ArtField::GetAccessFlags() {
@@ -61,10 +62,11 @@
   return object->GetField32(GetOffset(), IsVolatile());
 }
 
+template<bool kTransactionActive>
 inline void ArtField::Set32(Object* object, uint32_t new_value) {
   DCHECK(object != NULL) << PrettyField(this);
   DCHECK(!IsStatic() || (object == GetDeclaringClass()) || !Runtime::Current()->IsStarted());
-  object->SetField32(GetOffset(), new_value, IsVolatile());
+  object->SetField32<kTransactionActive>(GetOffset(), new_value, IsVolatile());
 }
 
 inline uint64_t ArtField::Get64(Object* object) {
@@ -73,10 +75,11 @@
   return object->GetField64(GetOffset(), IsVolatile());
 }
 
+template<bool kTransactionActive>
 inline void ArtField::Set64(Object* object, uint64_t new_value) {
   DCHECK(object != NULL) << PrettyField(this);
   DCHECK(!IsStatic() || (object == GetDeclaringClass()) || !Runtime::Current()->IsStarted());
-  object->SetField64(GetOffset(), new_value, IsVolatile());
+  object->SetField64<kTransactionActive>(GetOffset(), new_value, IsVolatile());
 }
 
 inline Object* ArtField::GetObj(Object* object) {
@@ -85,10 +88,11 @@
   return object->GetFieldObject<Object>(GetOffset(), IsVolatile());
 }
 
+template<bool kTransactionActive>
 inline void ArtField::SetObj(Object* object, Object* new_value) {
   DCHECK(object != NULL) << PrettyField(this);
   DCHECK(!IsStatic() || (object == GetDeclaringClass()) || !Runtime::Current()->IsStarted());
-  object->SetFieldObject(GetOffset(), new_value, IsVolatile());
+  object->SetFieldObject<kTransactionActive>(GetOffset(), new_value, IsVolatile());
 }
 
 inline bool ArtField::GetBoolean(Object* object) {
@@ -97,10 +101,11 @@
   return Get32(object);
 }
 
+template<bool kTransactionActive>
 inline void ArtField::SetBoolean(Object* object, bool z) {
   DCHECK_EQ(Primitive::kPrimBoolean, FieldHelper(this).GetTypeAsPrimitiveType())
       << PrettyField(this);
-  Set32(object, z);
+  Set32<kTransactionActive>(object, z);
 }
 
 inline int8_t ArtField::GetByte(Object* object) {
@@ -109,10 +114,11 @@
   return Get32(object);
 }
 
+template<bool kTransactionActive>
 inline void ArtField::SetByte(Object* object, int8_t b) {
   DCHECK_EQ(Primitive::kPrimByte, FieldHelper(this).GetTypeAsPrimitiveType())
       << PrettyField(this);
-  Set32(object, b);
+  Set32<kTransactionActive>(object, b);
 }
 
 inline uint16_t ArtField::GetChar(Object* object) {
@@ -121,10 +127,11 @@
   return Get32(object);
 }
 
+template<bool kTransactionActive>
 inline void ArtField::SetChar(Object* object, uint16_t c) {
   DCHECK_EQ(Primitive::kPrimChar, FieldHelper(this).GetTypeAsPrimitiveType())
        << PrettyField(this);
-  Set32(object, c);
+  Set32<kTransactionActive>(object, c);
 }
 
 inline int16_t ArtField::GetShort(Object* object) {
@@ -133,42 +140,45 @@
   return Get32(object);
 }
 
+template<bool kTransactionActive>
 inline void ArtField::SetShort(Object* object, int16_t s) {
   DCHECK_EQ(Primitive::kPrimShort, FieldHelper(this).GetTypeAsPrimitiveType())
        << PrettyField(this);
-  Set32(object, s);
+  Set32<kTransactionActive>(object, s);
 }
 
 inline int32_t ArtField::GetInt(Object* object) {
-#ifndef NDEBUG
-  Primitive::Type type = FieldHelper(this).GetTypeAsPrimitiveType();
-  CHECK(type == Primitive::kPrimInt || type == Primitive::kPrimFloat) << PrettyField(this);
-#endif
+  if (kIsDebugBuild) {
+    Primitive::Type type = FieldHelper(this).GetTypeAsPrimitiveType();
+    CHECK(type == Primitive::kPrimInt || type == Primitive::kPrimFloat) << PrettyField(this);
+  }
   return Get32(object);
 }
 
+template<bool kTransactionActive>
 inline void ArtField::SetInt(Object* object, int32_t i) {
-#ifndef NDEBUG
-  Primitive::Type type = FieldHelper(this).GetTypeAsPrimitiveType();
-  CHECK(type == Primitive::kPrimInt || type == Primitive::kPrimFloat) << PrettyField(this);
-#endif
-  Set32(object, i);
+  if (kIsDebugBuild) {
+    Primitive::Type type = FieldHelper(this).GetTypeAsPrimitiveType();
+    CHECK(type == Primitive::kPrimInt || type == Primitive::kPrimFloat) << PrettyField(this);
+  }
+  Set32<kTransactionActive>(object, i);
 }
 
 inline int64_t ArtField::GetLong(Object* object) {
-#ifndef NDEBUG
-  Primitive::Type type = FieldHelper(this).GetTypeAsPrimitiveType();
-  CHECK(type == Primitive::kPrimLong || type == Primitive::kPrimDouble) << PrettyField(this);
-#endif
+  if (kIsDebugBuild) {
+    Primitive::Type type = FieldHelper(this).GetTypeAsPrimitiveType();
+    CHECK(type == Primitive::kPrimLong || type == Primitive::kPrimDouble) << PrettyField(this);
+  }
   return Get64(object);
 }
 
+template<bool kTransactionActive>
 inline void ArtField::SetLong(Object* object, int64_t j) {
-#ifndef NDEBUG
-  Primitive::Type type = FieldHelper(this).GetTypeAsPrimitiveType();
-  CHECK(type == Primitive::kPrimLong || type == Primitive::kPrimDouble) << PrettyField(this);
-#endif
-  Set64(object, j);
+  if (kIsDebugBuild) {
+    Primitive::Type type = FieldHelper(this).GetTypeAsPrimitiveType();
+    CHECK(type == Primitive::kPrimLong || type == Primitive::kPrimDouble) << PrettyField(this);
+  }
+  Set64<kTransactionActive>(object, j);
 }
 
 inline float ArtField::GetFloat(Object* object) {
@@ -179,12 +189,13 @@
   return bits.GetF();
 }
 
+template<bool kTransactionActive>
 inline void ArtField::SetFloat(Object* object, float f) {
   DCHECK_EQ(Primitive::kPrimFloat, FieldHelper(this).GetTypeAsPrimitiveType())
        << PrettyField(this);
   JValue bits;
   bits.SetF(f);
-  Set32(object, bits.GetI());
+  Set32<kTransactionActive>(object, bits.GetI());
 }
 
 inline double ArtField::GetDouble(Object* object) {
@@ -195,12 +206,13 @@
   return bits.GetD();
 }
 
+template<bool kTransactionActive>
 inline void ArtField::SetDouble(Object* object, double d) {
   DCHECK_EQ(Primitive::kPrimDouble, FieldHelper(this).GetTypeAsPrimitiveType())
        << PrettyField(this);
   JValue bits;
   bits.SetD(d);
-  Set64(object, bits.GetJ());
+  Set64<kTransactionActive>(object, bits.GetJ());
 }
 
 inline Object* ArtField::GetObject(Object* object) {
@@ -209,10 +221,11 @@
   return GetObj(object);
 }
 
+template<bool kTransactionActive>
 inline void ArtField::SetObject(Object* object, Object* l) {
   DCHECK_EQ(Primitive::kPrimNot, FieldHelper(this).GetTypeAsPrimitiveType())
        << PrettyField(this);
-  SetObj(object, l);
+  SetObj<kTransactionActive>(object, l);
 }
 
 }  // namespace mirror
diff --git a/runtime/mirror/art_field.cc b/runtime/mirror/art_field.cc
index 29aade9..dd628ea 100644
--- a/runtime/mirror/art_field.cc
+++ b/runtime/mirror/art_field.cc
@@ -42,14 +42,15 @@
 
 void ArtField::SetOffset(MemberOffset num_bytes) {
   DCHECK(GetDeclaringClass()->IsLoaded() || GetDeclaringClass()->IsErroneous());
-#if 0  // TODO enable later in boot and under !NDEBUG
-  FieldHelper fh(this);
-  Primitive::Type type = fh.GetTypeAsPrimitiveType();
-  if (type == Primitive::kPrimDouble || type == Primitive::kPrimLong) {
-    DCHECK_ALIGNED(num_bytes.Uint32Value(), 8);
+  if (kIsDebugBuild && Runtime::Current()->IsCompiler() &&
+      !Runtime::Current()->UseCompileTimeClassPath()) {
+    Primitive::Type type = FieldHelper(this).GetTypeAsPrimitiveType();
+    if (type == Primitive::kPrimDouble || type == Primitive::kPrimLong) {
+      DCHECK_ALIGNED(num_bytes.Uint32Value(), 8);
+    }
   }
-#endif
-  SetField32(OFFSET_OF_OBJECT_MEMBER(ArtField, offset_), num_bytes.Uint32Value(), false);
+  // Not called within a transaction.
+  SetField32<false>(OFFSET_OF_OBJECT_MEMBER(ArtField, offset_), num_bytes.Uint32Value(), false);
 }
 
 void ArtField::VisitRoots(RootCallback* callback, void* arg) {
diff --git a/runtime/mirror/art_field.h b/runtime/mirror/art_field.h
index 716b736..46287c3 100644
--- a/runtime/mirror/art_field.h
+++ b/runtime/mirror/art_field.h
@@ -38,7 +38,8 @@
   uint32_t GetAccessFlags() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
   void SetAccessFlags(uint32_t new_access_flags) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
-    SetField32(OFFSET_OF_OBJECT_MEMBER(ArtField, access_flags_), new_access_flags, false);
+    // Not called within a transaction.
+    SetField32<false>(OFFSET_OF_OBJECT_MEMBER(ArtField, access_flags_), new_access_flags, false);
   }
 
   bool IsPublic() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
@@ -58,7 +59,8 @@
   }
 
   void SetDexFieldIndex(uint32_t new_idx) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
-    SetField32(OFFSET_OF_OBJECT_MEMBER(ArtField, field_dex_idx_), new_idx, false);
+    // Not called within a transaction.
+    SetField32<false>(OFFSET_OF_OBJECT_MEMBER(ArtField, field_dex_idx_), new_idx, false);
   }
 
   // Offset to field within an Object.
@@ -74,30 +76,42 @@
 
   // field access, null object for static fields
   bool GetBoolean(Object* object) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+  template<bool kTransactionActive>
   void SetBoolean(Object* object, bool z) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
   int8_t GetByte(Object* object) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+  template<bool kTransactionActive>
   void SetByte(Object* object, int8_t b) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
   uint16_t GetChar(Object* object) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+  template<bool kTransactionActive>
   void SetChar(Object* object, uint16_t c) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
   int16_t GetShort(Object* object) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+  template<bool kTransactionActive>
   void SetShort(Object* object, int16_t s) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
   int32_t GetInt(Object* object) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+  template<bool kTransactionActive>
   void SetInt(Object* object, int32_t i) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
   int64_t GetLong(Object* object) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+  template<bool kTransactionActive>
   void SetLong(Object* object, int64_t j) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
   float GetFloat(Object* object) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+  template<bool kTransactionActive>
   void SetFloat(Object* object, float f) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
   double GetDouble(Object* object) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+  template<bool kTransactionActive>
   void SetDouble(Object* object, double d) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
   Object* GetObject(Object* object) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+  template<bool kTransactionActive>
   void SetObject(Object* object, Object* l) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
   // Raw field accesses.
   uint32_t Get32(Object* object) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+  template<bool kTransactionActive>
   void Set32(Object* object, uint32_t new_value) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
   uint64_t Get64(Object* object) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+  template<bool kTransactionActive>
   void Set64(Object* object, uint64_t new_value) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
   Object* GetObj(Object* object) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+  template<bool kTransactionActive>
   void SetObj(Object* object, Object* new_value) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
   static Class* GetJavaLangReflectArtField() {
diff --git a/runtime/mirror/art_method-inl.h b/runtime/mirror/art_method-inl.h
index 8ef3be8..d347724 100644
--- a/runtime/mirror/art_method-inl.h
+++ b/runtime/mirror/art_method-inl.h
@@ -36,7 +36,8 @@
 }
 
 inline void ArtMethod::SetDeclaringClass(Class *new_declaring_class) {
-  SetFieldObject(OFFSET_OF_OBJECT_MEMBER(ArtMethod, declaring_class_), new_declaring_class, false);
+  SetFieldObject<false>(OFFSET_OF_OBJECT_MEMBER(ArtMethod, declaring_class_),
+                        new_declaring_class, false);
 }
 
 inline uint32_t ArtMethod::GetAccessFlags() {
diff --git a/runtime/mirror/art_method.cc b/runtime/mirror/art_method.cc
index 67e6c7d..b5c87ad 100644
--- a/runtime/mirror/art_method.cc
+++ b/runtime/mirror/art_method.cc
@@ -73,18 +73,18 @@
 }
 
 void ArtMethod::SetDexCacheStrings(ObjectArray<String>* new_dex_cache_strings) {
-  SetFieldObject(OFFSET_OF_OBJECT_MEMBER(ArtMethod, dex_cache_strings_),
-                 new_dex_cache_strings, false);
+  SetFieldObject<false>(OFFSET_OF_OBJECT_MEMBER(ArtMethod, dex_cache_strings_),
+                        new_dex_cache_strings, false);
 }
 
 void ArtMethod::SetDexCacheResolvedMethods(ObjectArray<ArtMethod>* new_dex_cache_methods) {
-  SetFieldObject(OFFSET_OF_OBJECT_MEMBER(ArtMethod, dex_cache_resolved_methods_),
-                 new_dex_cache_methods, false);
+  SetFieldObject<false>(OFFSET_OF_OBJECT_MEMBER(ArtMethod, dex_cache_resolved_methods_),
+                        new_dex_cache_methods, false);
 }
 
 void ArtMethod::SetDexCacheResolvedTypes(ObjectArray<Class>* new_dex_cache_classes) {
-  SetFieldObject(OFFSET_OF_OBJECT_MEMBER(ArtMethod, dex_cache_resolved_types_),
-                 new_dex_cache_classes, false);
+  SetFieldObject<false>(OFFSET_OF_OBJECT_MEMBER(ArtMethod, dex_cache_resolved_types_),
+                        new_dex_cache_classes, false);
 }
 
 size_t ArtMethod::NumArgRegisters(const StringPiece& shorty) {
@@ -337,8 +337,8 @@
 #else
     SetNativeMethod(reinterpret_cast<void*>(art_work_around_app_jni_bugs));
 #endif
-    SetFieldPtr<const uint8_t*>(OFFSET_OF_OBJECT_MEMBER(ArtMethod, gc_map_),
-        reinterpret_cast<const uint8_t*>(native_method), false);
+    SetFieldPtr<false>(OFFSET_OF_OBJECT_MEMBER(ArtMethod, gc_map_),
+                       reinterpret_cast<const uint8_t*>(native_method), false);
   }
 }
 
@@ -349,8 +349,8 @@
 }
 
 void ArtMethod::SetNativeMethod(const void* native_method) {
-  SetFieldPtr<const void*>(OFFSET_OF_OBJECT_MEMBER(ArtMethod, entry_point_from_jni_),
-      native_method, false);
+  SetFieldPtr<false>(OFFSET_OF_OBJECT_MEMBER(ArtMethod, entry_point_from_jni_),
+                     native_method, false);
 }
 
 }  // namespace mirror
diff --git a/runtime/mirror/art_method.h b/runtime/mirror/art_method.h
index e678503..71cc7af 100644
--- a/runtime/mirror/art_method.h
+++ b/runtime/mirror/art_method.h
@@ -56,7 +56,8 @@
   uint32_t GetAccessFlags() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
   void SetAccessFlags(uint32_t new_access_flags) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
-    SetField32(OFFSET_OF_OBJECT_MEMBER(ArtMethod, access_flags_), new_access_flags, false);
+    // Not called within a transaction.
+    SetField32<false>(OFFSET_OF_OBJECT_MEMBER(ArtMethod, access_flags_), new_access_flags, false);
   }
 
   // Approximate what kind of method call would be used for this method.
@@ -156,7 +157,8 @@
   }
 
   void SetMethodIndex(uint16_t new_method_index) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
-    SetField32(OFFSET_OF_OBJECT_MEMBER(ArtMethod, method_index_), new_method_index, false);
+    // Not called within a transaction.
+    SetField32<false>(OFFSET_OF_OBJECT_MEMBER(ArtMethod, method_index_), new_method_index, false);
   }
 
   static MemberOffset MethodIndexOffset() {
@@ -168,7 +170,8 @@
   }
 
   void SetCodeItemOffset(uint32_t new_code_off) {
-    SetField32(OFFSET_OF_OBJECT_MEMBER(ArtMethod, dex_code_item_offset_), new_code_off, false);
+    // Not called within a transaction.
+    SetField32<false>(OFFSET_OF_OBJECT_MEMBER(ArtMethod, dex_code_item_offset_), new_code_off, false);
   }
 
   // Number of 32bit registers that would be required to hold all the arguments
@@ -177,7 +180,8 @@
   uint32_t GetDexMethodIndex() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
   void SetDexMethodIndex(uint32_t new_idx) {
-    SetField32(OFFSET_OF_OBJECT_MEMBER(ArtMethod, dex_method_index_), new_idx, false);
+    // Not called within a transaction.
+    SetField32<false>(OFFSET_OF_OBJECT_MEMBER(ArtMethod, dex_method_index_), new_idx, false);
   }
 
   ObjectArray<String>* GetDexCacheStrings() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
@@ -216,9 +220,8 @@
   }
 
   void SetEntryPointFromInterpreter(EntryPointFromInterpreter* entry_point_from_interpreter) {
-    SetFieldPtr<EntryPointFromInterpreter*>(
-        OFFSET_OF_OBJECT_MEMBER(ArtMethod, entry_point_from_interpreter_),
-        entry_point_from_interpreter, false);
+    SetFieldPtr<false>(OFFSET_OF_OBJECT_MEMBER(ArtMethod, entry_point_from_interpreter_),
+                       entry_point_from_interpreter, false);
   }
 
   static MemberOffset EntryPointFromPortableCompiledCodeOffset() {
@@ -230,8 +233,8 @@
   }
 
   void SetEntryPointFromPortableCompiledCode(const void* entry_point_from_portable_compiled_code) {
-    SetFieldPtr<const void*>(EntryPointFromPortableCompiledCodeOffset(),
-        entry_point_from_portable_compiled_code, false);
+    SetFieldPtr<false>(EntryPointFromPortableCompiledCodeOffset(),
+                       entry_point_from_portable_compiled_code, false);
   }
 
   static MemberOffset EntryPointFromQuickCompiledCodeOffset() {
@@ -243,8 +246,8 @@
   }
 
   void SetEntryPointFromQuickCompiledCode(const void* entry_point_from_quick_compiled_code) {
-    SetFieldPtr<const void*>(EntryPointFromQuickCompiledCodeOffset(),
-        entry_point_from_quick_compiled_code, false);
+    SetFieldPtr<false>(EntryPointFromQuickCompiledCodeOffset(),
+                       entry_point_from_quick_compiled_code, false);
   }
 
 
@@ -277,8 +280,8 @@
   }
 
   void SetMappingTable(const uint8_t* mapping_table) {
-    SetFieldPtr<const uint8_t*>(OFFSET_OF_OBJECT_MEMBER(ArtMethod, quick_mapping_table_),
-                                mapping_table, false);
+    SetFieldPtr<false>(OFFSET_OF_OBJECT_MEMBER(ArtMethod, quick_mapping_table_),
+                       mapping_table, false);
   }
 
   uint32_t GetOatMappingTableOffset();
@@ -292,8 +295,7 @@
   }
 
   void SetVmapTable(const uint8_t* vmap_table) {
-    SetFieldPtr<const uint8_t*>(OFFSET_OF_OBJECT_MEMBER(ArtMethod, quick_vmap_table_), vmap_table,
-        false);
+    SetFieldPtr<false>(OFFSET_OF_OBJECT_MEMBER(ArtMethod, quick_vmap_table_), vmap_table, false);
   }
 
   uint32_t GetOatVmapTableOffset();
@@ -304,7 +306,7 @@
     return GetFieldPtr<uint8_t*>(OFFSET_OF_OBJECT_MEMBER(ArtMethod, gc_map_), false);
   }
   void SetNativeGcMap(const uint8_t* data) {
-    SetFieldPtr<const uint8_t*>(OFFSET_OF_OBJECT_MEMBER(ArtMethod, gc_map_), data, false);
+    SetFieldPtr<false>(OFFSET_OF_OBJECT_MEMBER(ArtMethod, gc_map_), data, false);
   }
 
   // When building the oat need a convenient place to stuff the offset of the native GC map.
@@ -319,8 +321,9 @@
   }
 
   void SetFrameSizeInBytes(size_t new_frame_size_in_bytes) {
-    SetField32(OFFSET_OF_OBJECT_MEMBER(ArtMethod, quick_frame_size_in_bytes_),
-               new_frame_size_in_bytes, false);
+    // Not called within a transaction.
+    SetField32<false>(OFFSET_OF_OBJECT_MEMBER(ArtMethod, quick_frame_size_in_bytes_),
+                      new_frame_size_in_bytes, false);
   }
 
   size_t GetReturnPcOffsetInBytes() {
@@ -358,8 +361,9 @@
   }
 
   void SetCoreSpillMask(uint32_t core_spill_mask) {
-    // Computed during compilation
-    SetField32(OFFSET_OF_OBJECT_MEMBER(ArtMethod, quick_core_spill_mask_), core_spill_mask, false);
+    // Computed during compilation.
+    // Not called within a transaction.
+    SetField32<false>(OFFSET_OF_OBJECT_MEMBER(ArtMethod, quick_core_spill_mask_), core_spill_mask, false);
   }
 
   uint32_t GetFpSpillMask() {
@@ -367,8 +371,9 @@
   }
 
   void SetFpSpillMask(uint32_t fp_spill_mask) {
-    // Computed during compilation
-    SetField32(OFFSET_OF_OBJECT_MEMBER(ArtMethod, quick_fp_spill_mask_), fp_spill_mask, false);
+    // Computed during compilation.
+    // Not called within a transaction.
+    SetField32<false>(OFFSET_OF_OBJECT_MEMBER(ArtMethod, quick_fp_spill_mask_), fp_spill_mask, false);
   }
 
   // Is this a CalleSaveMethod or ResolutionMethod and therefore doesn't adhere to normal
diff --git a/runtime/mirror/class-inl.h b/runtime/mirror/class-inl.h
index a5f743b..4c2bdb0 100644
--- a/runtime/mirror/class-inl.h
+++ b/runtime/mirror/class-inl.h
@@ -64,8 +64,8 @@
   DCHECK(NULL == GetFieldObject<ObjectArray<ArtMethod> >(
       OFFSET_OF_OBJECT_MEMBER(Class, direct_methods_), false));
   DCHECK_NE(0, new_direct_methods->GetLength());
-  SetFieldObject(OFFSET_OF_OBJECT_MEMBER(Class, direct_methods_),
-                 new_direct_methods, false);
+  SetFieldObject<false>(OFFSET_OF_OBJECT_MEMBER(Class, direct_methods_),
+                        new_direct_methods, false);
 }
 
 inline ArtMethod* Class::GetDirectMethod(int32_t i) {
@@ -77,7 +77,7 @@
   ObjectArray<ArtMethod>* direct_methods =
       GetFieldObject<ObjectArray<ArtMethod> >(
           OFFSET_OF_OBJECT_MEMBER(Class, direct_methods_), false);
-  direct_methods->Set(i, f);
+  direct_methods->Set<false>(i, f);
 }
 
 // Returns the number of static, private, and constructor methods.
@@ -93,10 +93,10 @@
 
 inline void Class::SetVirtualMethods(ObjectArray<ArtMethod>* new_virtual_methods) {
   // TODO: we reassign virtual methods to grow the table for miranda
-  // methods.. they should really just be assigned once
+  // methods.. they should really just be assigned once.
   DCHECK_NE(0, new_virtual_methods->GetLength());
-  SetFieldObject(OFFSET_OF_OBJECT_MEMBER(Class, virtual_methods_),
-                 new_virtual_methods, false);
+  SetFieldObject<false>(OFFSET_OF_OBJECT_MEMBER(Class, virtual_methods_),
+                        new_virtual_methods, false);
 }
 
 inline uint32_t Class::NumVirtualMethods() {
@@ -118,7 +118,7 @@
   ObjectArray<ArtMethod>* virtual_methods =
       GetFieldObject<ObjectArray<ArtMethod> >(
           OFFSET_OF_OBJECT_MEMBER(Class, virtual_methods_), false);
-  virtual_methods->Set(i, f);
+  virtual_methods->Set<false>(i, f);
 }
 
 inline ObjectArray<ArtMethod>* Class::GetVTable() {
@@ -132,7 +132,7 @@
 }
 
 inline void Class::SetVTable(ObjectArray<ArtMethod>* new_vtable) {
-  SetFieldObject(OFFSET_OF_OBJECT_MEMBER(Class, vtable_), new_vtable, false);
+  SetFieldObject<false>(OFFSET_OF_OBJECT_MEMBER(Class, vtable_), new_vtable, false);
 }
 
 inline ObjectArray<ArtMethod>* Class::GetImTable() {
@@ -140,7 +140,7 @@
 }
 
 inline void Class::SetImTable(ObjectArray<ArtMethod>* new_imtable) {
-  SetFieldObject(OFFSET_OF_OBJECT_MEMBER(Class, imtable_), new_imtable, false);
+  SetFieldObject<false>(OFFSET_OF_OBJECT_MEMBER(Class, imtable_), new_imtable, false);
 }
 
 inline bool Class::Implements(Class* klass) {
@@ -347,7 +347,7 @@
 }
 
 inline void Class::SetIfTable(IfTable* new_iftable) {
-  SetFieldObject(OFFSET_OF_OBJECT_MEMBER(Class, iftable_), new_iftable, false);
+  SetFieldObject<false>(OFFSET_OF_OBJECT_MEMBER(Class, iftable_), new_iftable, false);
 }
 
 inline ObjectArray<ArtField>* Class::GetIFields() {
@@ -359,7 +359,7 @@
     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
   DCHECK(NULL == GetFieldObject<ObjectArray<ArtField> >(
       OFFSET_OF_OBJECT_MEMBER(Class, ifields_), false));
-  SetFieldObject(OFFSET_OF_OBJECT_MEMBER(Class, ifields_), new_ifields, false);
+  SetFieldObject<false>(OFFSET_OF_OBJECT_MEMBER(Class, ifields_), new_ifields, false);
 }
 
 inline ObjectArray<ArtField>* Class::GetSFields() {
@@ -371,7 +371,7 @@
     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
   DCHECK(NULL == GetFieldObject<ObjectArray<ArtField> >(
       OFFSET_OF_OBJECT_MEMBER(Class, sfields_), false));
-  SetFieldObject(OFFSET_OF_OBJECT_MEMBER(Class, sfields_), new_sfields, false);
+  SetFieldObject<false>(OFFSET_OF_OBJECT_MEMBER(Class, sfields_), new_sfields, false);
 }
 
 inline uint32_t Class::NumStaticFields() {
@@ -387,7 +387,7 @@
     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
   ObjectArray<ArtField>* sfields= GetFieldObject<ObjectArray<ArtField> >(
       OFFSET_OF_OBJECT_MEMBER(Class, sfields_), false);
-  sfields->Set(i, f);
+  sfields->Set<false>(i, f);
 }
 
 inline uint32_t Class::NumInstanceFields() {
@@ -403,12 +403,16 @@
     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
   ObjectArray<ArtField>* ifields= GetFieldObject<ObjectArray<ArtField> >(
       OFFSET_OF_OBJECT_MEMBER(Class, ifields_), false);
-  ifields->Set(i, f);
+  ifields->Set<false>(i, f);
 }
 
 inline void Class::SetVerifyErrorClass(Class* klass) {
   CHECK(klass != NULL) << PrettyClass(this);
-  SetFieldObject(OFFSET_OF_OBJECT_MEMBER(Class, verify_error_class_), klass, false);
+  if (Runtime::Current()->IsActiveTransaction()) {
+    SetFieldObject<true>(OFFSET_OF_OBJECT_MEMBER(Class, verify_error_class_), klass, false);
+  } else {
+    SetFieldObject<false>(OFFSET_OF_OBJECT_MEMBER(Class, verify_error_class_), klass, false);
+  }
 }
 
 inline uint32_t Class::GetAccessFlags() {
@@ -425,7 +429,11 @@
   return GetFieldObject<String>(OFFSET_OF_OBJECT_MEMBER(Class, name_), false);
 }
 inline void Class::SetName(String* name) {
-  SetFieldObject(OFFSET_OF_OBJECT_MEMBER(Class, name_), name, false);
+  if (Runtime::Current()->IsActiveTransaction()) {
+    SetFieldObject<true>(OFFSET_OF_OBJECT_MEMBER(Class, name_), name, false);
+  } else {
+    SetFieldObject<false>(OFFSET_OF_OBJECT_MEMBER(Class, name_), name, false);
+  }
 }
 
 inline void Class::CheckObjectAlloc() {
diff --git a/runtime/mirror/class.cc b/runtime/mirror/class.cc
index 99a35e3..6446d02 100644
--- a/runtime/mirror/class.cc
+++ b/runtime/mirror/class.cc
@@ -113,7 +113,11 @@
     self->SetException(gc_safe_throw_location, old_exception.get());
   }
   CHECK(sizeof(Status) == sizeof(uint32_t)) << PrettyClass(this);
-  SetField32(OFFSET_OF_OBJECT_MEMBER(Class, status_), new_status, false);
+  if (Runtime::Current()->IsActiveTransaction()) {
+    SetField32<true>(OFFSET_OF_OBJECT_MEMBER(Class, status_), new_status, false);
+  } else {
+    SetField32<false>(OFFSET_OF_OBJECT_MEMBER(Class, status_), new_status, false);
+  }
   // Classes that are being resolved or initialized need to notify waiters that the class status
   // changed. See ClassLinker::EnsureResolved and ClassLinker::WaitForInitializeClass.
   if ((old_status >= kStatusResolved || new_status >= kStatusResolved) &&
@@ -123,7 +127,7 @@
 }
 
 void Class::SetDexCache(DexCache* new_dex_cache) {
-  SetFieldObject(OFFSET_OF_OBJECT_MEMBER(Class, dex_cache_), new_dex_cache, false);
+  SetFieldObject<false>(OFFSET_OF_OBJECT_MEMBER(Class, dex_cache_), new_dex_cache, false);
 }
 
 void Class::SetClassSize(uint32_t new_class_size) {
@@ -131,7 +135,8 @@
     DumpClass(LOG(ERROR), kDumpClassFullDetail);
     CHECK_GE(new_class_size, GetClassSize()) << " class=" << PrettyTypeOf(this);
   }
-  SetField32(OFFSET_OF_OBJECT_MEMBER(Class, class_size_), new_class_size, false);
+  // Not called within a transaction.
+  SetField32<false>(OFFSET_OF_OBJECT_MEMBER(Class, class_size_), new_class_size, false);
 }
 
 // Return the class' name. The exact format is bizarre, but it's the specified behavior for
@@ -254,8 +259,9 @@
     }
     CHECK_EQ((size_t)__builtin_popcount(new_reference_offsets), count);
   }
-  SetField32(OFFSET_OF_OBJECT_MEMBER(Class, reference_instance_offsets_),
-             new_reference_offsets, false);
+  // Not called within a transaction.
+  SetField32<false>(OFFSET_OF_OBJECT_MEMBER(Class, reference_instance_offsets_),
+                    new_reference_offsets, false);
 }
 
 void Class::SetReferenceStaticOffsets(uint32_t new_reference_offsets) {
@@ -265,8 +271,9 @@
     CHECK_EQ((size_t)__builtin_popcount(new_reference_offsets),
              NumReferenceStaticFieldsDuringLinking());
   }
-  SetField32(OFFSET_OF_OBJECT_MEMBER(Class, reference_static_offsets_),
-             new_reference_offsets, false);
+  // Not called within a transaction.
+  SetField32<false>(OFFSET_OF_OBJECT_MEMBER(Class, reference_static_offsets_),
+                    new_reference_offsets, false);
 }
 
 bool Class::IsInSamePackage(const StringPiece& descriptor1, const StringPiece& descriptor2) {
@@ -332,7 +339,11 @@
 }
 
 void Class::SetClassLoader(ClassLoader* new_class_loader) {
-  SetFieldObject(OFFSET_OF_OBJECT_MEMBER(Class, class_loader_), new_class_loader, false);
+  if (Runtime::Current()->IsActiveTransaction()) {
+    SetFieldObject<true>(OFFSET_OF_OBJECT_MEMBER(Class, class_loader_), new_class_loader, false);
+  } else {
+    SetFieldObject<false>(OFFSET_OF_OBJECT_MEMBER(Class, class_loader_), new_class_loader, false);
+  }
 }
 
 ArtMethod* Class::FindInterfaceMethod(const StringPiece& name, const Signature& signature) {
diff --git a/runtime/mirror/class.h b/runtime/mirror/class.h
index 82c8264..cd8504b 100644
--- a/runtime/mirror/class.h
+++ b/runtime/mirror/class.h
@@ -174,7 +174,8 @@
   uint32_t GetAccessFlags() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
   void SetAccessFlags(uint32_t new_access_flags) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
-    SetField32(OFFSET_OF_OBJECT_MEMBER(Class, access_flags_), new_access_flags, false);
+    // Not called within a transaction.
+    SetField32<false>(OFFSET_OF_OBJECT_MEMBER(Class, access_flags_), new_access_flags, false);
   }
 
   // Returns true if the class is an interface.
@@ -275,7 +276,7 @@
 
   void SetPrimitiveType(Primitive::Type new_type) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     DCHECK_EQ(sizeof(Primitive::Type), sizeof(int32_t));
-    SetField32(OFFSET_OF_OBJECT_MEMBER(Class, primitive_type_), new_type, false);
+    SetField32<false>(OFFSET_OF_OBJECT_MEMBER(Class, primitive_type_), new_type, false);
   }
 
   // Returns true if the class is a primitive type.
@@ -357,7 +358,11 @@
   void SetComponentType(Class* new_component_type) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     DCHECK(GetComponentType() == NULL);
     DCHECK(new_component_type != NULL);
-    SetFieldObject(ComponentTypeOffset(), new_component_type, false);
+    if (Runtime::Current()->IsActiveTransaction()) {
+      SetFieldObject<true>(ComponentTypeOffset(), new_component_type, false);
+    } else {
+      SetFieldObject<false>(ComponentTypeOffset(), new_component_type, false);
+    }
   }
 
   size_t GetComponentSize() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
@@ -406,7 +411,8 @@
 
   void SetObjectSize(uint32_t new_object_size) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     DCHECK(!IsVariableSize());
-    return SetField32(OFFSET_OF_OBJECT_MEMBER(Class, object_size_), new_object_size, false);
+    // Not called within a transaction.
+    return SetField32<false>(OFFSET_OF_OBJECT_MEMBER(Class, object_size_), new_object_size, false);
   }
 
   // Returns true if this class is in the same packages as that class.
@@ -499,7 +505,7 @@
                                                    false);
     DCHECK(old_super_class == nullptr || old_super_class == new_super_class);
     DCHECK(new_super_class != nullptr);
-    SetFieldObject(OFFSET_OF_OBJECT_MEMBER(Class, super_class_), new_super_class, false);
+    SetFieldObject<false>(OFFSET_OF_OBJECT_MEMBER(Class, super_class_), new_super_class, false);
   }
 
   bool HasSuperClass() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
@@ -672,7 +678,9 @@
   }
 
   void SetNumReferenceInstanceFields(uint32_t new_num) {
-    SetField32(OFFSET_OF_OBJECT_MEMBER(Class, num_reference_instance_fields_), new_num, false);
+    // Not called within a transaction.
+    SetField32<false>(OFFSET_OF_OBJECT_MEMBER(Class, num_reference_instance_fields_), new_num,
+                      false);
   }
 
   uint32_t GetReferenceInstanceOffsets() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
@@ -700,7 +708,8 @@
   }
 
   void SetNumReferenceStaticFields(uint32_t new_num) {
-    SetField32(OFFSET_OF_OBJECT_MEMBER(Class, num_reference_static_fields_), new_num, false);
+    // Not called within a transaction.
+    SetField32<false>(OFFSET_OF_OBJECT_MEMBER(Class, num_reference_static_fields_), new_num, false);
   }
 
   // Gets the static fields of the class.
@@ -763,7 +772,13 @@
   }
 
   void SetClinitThreadId(pid_t new_clinit_thread_id) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
-    SetField32(OFFSET_OF_OBJECT_MEMBER(Class, clinit_thread_id_), new_clinit_thread_id, false);
+    if (Runtime::Current()->IsActiveTransaction()) {
+      SetField32<true>(OFFSET_OF_OBJECT_MEMBER(Class, clinit_thread_id_), new_clinit_thread_id,
+                       false);
+    } else {
+      SetField32<false>(OFFSET_OF_OBJECT_MEMBER(Class, clinit_thread_id_), new_clinit_thread_id,
+                        false);
+    }
   }
 
   Class* GetVerifyErrorClass() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
@@ -776,7 +791,8 @@
   }
 
   void SetDexClassDefIndex(uint16_t class_def_idx) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
-    SetField32(OFFSET_OF_OBJECT_MEMBER(Class, dex_class_def_idx_), class_def_idx, false);
+    // Not called within a transaction.
+    SetField32<false>(OFFSET_OF_OBJECT_MEMBER(Class, dex_class_def_idx_), class_def_idx, false);
   }
 
   uint16_t GetDexTypeIndex() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
@@ -784,7 +800,8 @@
   }
 
   void SetDexTypeIndex(uint16_t type_idx) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
-    SetField32(OFFSET_OF_OBJECT_MEMBER(Class, dex_type_idx_), type_idx, false);
+    // Not called within a transaction.
+    SetField32<false>(OFFSET_OF_OBJECT_MEMBER(Class, dex_type_idx_), type_idx, false);
   }
 
   static Class* GetJavaLangClass() {
diff --git a/runtime/mirror/dex_cache.cc b/runtime/mirror/dex_cache.cc
index fa0900c..0a77db3 100644
--- a/runtime/mirror/dex_cache.cc
+++ b/runtime/mirror/dex_cache.cc
@@ -44,12 +44,12 @@
   CHECK(resolved_methods != nullptr);
   CHECK(resolved_fields != nullptr);
 
-  SetFieldPtr(OFFSET_OF_OBJECT_MEMBER(DexCache, dex_file_), dex_file, false);
-  SetFieldObject(OFFSET_OF_OBJECT_MEMBER(DexCache, location_), location, false);
-  SetFieldObject(StringsOffset(), strings, false);
-  SetFieldObject(OFFSET_OF_OBJECT_MEMBER(DexCache, resolved_types_), resolved_types, false);
-  SetFieldObject(ResolvedMethodsOffset(), resolved_methods, false);
-  SetFieldObject(ResolvedFieldsOffset(), resolved_fields, false);
+  SetFieldPtr<false>(OFFSET_OF_OBJECT_MEMBER(DexCache, dex_file_), dex_file, false);
+  SetFieldObject<false>(OFFSET_OF_OBJECT_MEMBER(DexCache, location_), location, false);
+  SetFieldObject<false>(StringsOffset(), strings, false);
+  SetFieldObject<false>(OFFSET_OF_OBJECT_MEMBER(DexCache, resolved_types_), resolved_types, false);
+  SetFieldObject<false>(ResolvedMethodsOffset(), resolved_methods, false);
+  SetFieldObject<false>(ResolvedFieldsOffset(), resolved_fields, false);
 
   Runtime* runtime = Runtime::Current();
   if (runtime->HasResolutionMethod()) {
@@ -57,7 +57,7 @@
     ArtMethod* trampoline = runtime->GetResolutionMethod();
     size_t length = resolved_methods->GetLength();
     for (size_t i = 0; i < length; i++) {
-      resolved_methods->SetWithoutChecks(i, trampoline);
+      resolved_methods->SetWithoutChecks<false>(i, trampoline);
     }
   }
 }
@@ -69,7 +69,7 @@
   size_t length = resolved_methods->GetLength();
   for (size_t i = 0; i < length; i++) {
     if (resolved_methods->GetWithoutChecks(i) == nullptr) {
-      resolved_methods->SetWithoutChecks(i, trampoline);
+      resolved_methods->SetWithoutChecks<false>(i, trampoline);
     }
   }
 }
diff --git a/runtime/mirror/dex_cache.h b/runtime/mirror/dex_cache.h
index 99529f0..843f860 100644
--- a/runtime/mirror/dex_cache.h
+++ b/runtime/mirror/dex_cache.h
@@ -90,6 +90,7 @@
 
   void SetResolvedString(uint32_t string_idx, String* resolved)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+    // TODO default transaction support.
     GetStrings()->Set(string_idx, resolved);
   }
 
@@ -99,6 +100,7 @@
 
   void SetResolvedType(uint32_t type_idx, Class* resolved)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+    // TODO default transaction support.
     GetResolvedTypes()->Set(type_idx, resolved);
   }
 
@@ -140,7 +142,7 @@
   }
 
   void SetDexFile(const DexFile* dex_file) {
-    return SetFieldPtr(OFFSET_OF_OBJECT_MEMBER(DexCache, dex_file_), dex_file, false);
+    return SetFieldPtr<false>(OFFSET_OF_OBJECT_MEMBER(DexCache, dex_file_), dex_file, false);
   }
 
  private:
diff --git a/runtime/mirror/iftable-inl.h b/runtime/mirror/iftable-inl.h
index 9d5fa74..ec3e514 100644
--- a/runtime/mirror/iftable-inl.h
+++ b/runtime/mirror/iftable-inl.h
@@ -26,7 +26,7 @@
   DCHECK(interface != NULL);
   DCHECK(interface->IsInterface());
   DCHECK(Get((i * kMax) + kInterface) == NULL);
-  Set((i * kMax) + kInterface, interface);
+  Set<false>((i * kMax) + kInterface, interface);
 }
 
 }  // namespace mirror
diff --git a/runtime/mirror/iftable.h b/runtime/mirror/iftable.h
index be83d03..bb4cd41 100644
--- a/runtime/mirror/iftable.h
+++ b/runtime/mirror/iftable.h
@@ -52,7 +52,7 @@
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     DCHECK(new_ma != NULL);
     DCHECK(Get((i * kMax) + kMethodArray) == NULL);
-    Set((i * kMax) + kMethodArray, new_ma);
+    Set<false>((i * kMax) + kMethodArray, new_ma);
   }
 
   size_t Count() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
diff --git a/runtime/mirror/object-inl.h b/runtime/mirror/object-inl.h
index 2392561..70291c1 100644
--- a/runtime/mirror/object-inl.h
+++ b/runtime/mirror/object-inl.h
@@ -40,7 +40,10 @@
   // new_klass may be NULL prior to class linker initialization.
   // We don't mark the card as this occurs as part of object allocation. Not all objects have
   // backing cards, such as large objects.
-  SetFieldObjectWithoutWriteBarrier(OFFSET_OF_OBJECT_MEMBER(Object, klass_), new_klass, false, false);
+  // We use non transactional version since we can't undo this write. We also disable checking as
+  // we may run in transaction mode here.
+  SetFieldObjectWithoutWriteBarrier<false, false>(OFFSET_OF_OBJECT_MEMBER(Object, klass_),
+                                                  new_klass, false, false);
 }
 
 inline LockWord Object::GetLockWord() {
@@ -48,12 +51,14 @@
 }
 
 inline void Object::SetLockWord(LockWord new_val) {
-  SetField32(OFFSET_OF_OBJECT_MEMBER(Object, monitor_), new_val.GetValue(), true);
+  // Force use of non-transactional mode and do not check.
+  SetField32<false, false>(OFFSET_OF_OBJECT_MEMBER(Object, monitor_), new_val.GetValue(), true);
 }
 
 inline bool Object::CasLockWord(LockWord old_val, LockWord new_val) {
-  return CasField32(OFFSET_OF_OBJECT_MEMBER(Object, monitor_), old_val.GetValue(),
-                    new_val.GetValue());
+  // Force use of non-transactional mode and do not check.
+  return CasField32<false, false>(OFFSET_OF_OBJECT_MEMBER(Object, monitor_), old_val.GetValue(),
+                                  new_val.GetValue());
 }
 
 inline uint32_t Object::GetLockOwnerThreadId() {
@@ -199,6 +204,18 @@
   return down_cast<LongArray*>(this);
 }
 
+inline FloatArray* Object::AsFloatArray() {
+  DCHECK(GetClass()->IsArrayClass());
+  DCHECK(GetClass()->GetComponentType()->IsPrimitiveFloat());
+  return down_cast<FloatArray*>(this);
+}
+
+inline DoubleArray* Object::AsDoubleArray() {
+  DCHECK(GetClass()->IsArrayClass());
+  DCHECK(GetClass()->GetComponentType()->IsPrimitiveDouble());
+  return down_cast<DoubleArray*>(this);
+}
+
 inline String* Object::AsString() {
   DCHECK(GetClass()->IsStringClass());
   return down_cast<String*>(this);
@@ -253,8 +270,16 @@
   }
 }
 
+template<bool kTransactionActive, bool kCheckTransaction>
 inline void Object::SetField32(MemberOffset field_offset, int32_t new_value, bool is_volatile,
                                bool this_is_valid) {
+  if (kCheckTransaction) {
+    DCHECK_EQ(kTransactionActive, Runtime::Current()->IsActiveTransaction());
+  }
+  if (kTransactionActive) {
+    Runtime::Current()->RecordWriteField32(this, field_offset, GetField32(field_offset, is_volatile),
+                                           is_volatile);
+  }
   if (this_is_valid) {
     VerifyObject(this);
   }
@@ -269,7 +294,14 @@
   }
 }
 
+template<bool kTransactionActive, bool kCheckTransaction>
 inline bool Object::CasField32(MemberOffset field_offset, int32_t old_value, int32_t new_value) {
+  if (kCheckTransaction) {
+    DCHECK_EQ(kTransactionActive, Runtime::Current()->IsActiveTransaction());
+  }
+  if (kTransactionActive) {
+    Runtime::Current()->RecordWriteField32(this, field_offset, old_value, true);
+  }
   VerifyObject(this);
   byte* raw_addr = reinterpret_cast<byte*>(this) + field_offset.Int32Value();
   volatile int32_t* addr = reinterpret_cast<volatile int32_t*>(raw_addr);
@@ -289,8 +321,16 @@
   }
 }
 
+template<bool kTransactionActive, bool kCheckTransaction>
 inline void Object::SetField64(MemberOffset field_offset, int64_t new_value, bool is_volatile,
                                bool this_is_valid) {
+  if (kCheckTransaction) {
+    DCHECK_EQ(kTransactionActive, Runtime::Current()->IsActiveTransaction());
+  }
+  if (kTransactionActive) {
+    Runtime::Current()->RecordWriteField64(this, field_offset, GetField64(field_offset, is_volatile),
+                                           is_volatile);
+  }
   if (this_is_valid) {
     VerifyObject(this);
   }
@@ -309,7 +349,14 @@
   }
 }
 
+template<bool kTransactionActive, bool kCheckTransaction>
 inline bool Object::CasField64(MemberOffset field_offset, int64_t old_value, int64_t new_value) {
+  if (kCheckTransaction) {
+    DCHECK_EQ(kTransactionActive, Runtime::Current()->IsActiveTransaction());
+  }
+  if (kTransactionActive) {
+    Runtime::Current()->RecordWriteField64(this, field_offset, old_value, true);
+  }
   VerifyObject(this);
   byte* raw_addr = reinterpret_cast<byte*>(this) + field_offset.Int32Value();
   volatile int64_t* addr = reinterpret_cast<volatile int64_t*>(raw_addr);
@@ -331,8 +378,17 @@
   return result;
 }
 
+template<bool kTransactionActive, bool kCheckTransaction>
 inline void Object::SetFieldObjectWithoutWriteBarrier(MemberOffset field_offset, Object* new_value,
                                                       bool is_volatile, bool this_is_valid) {
+  if (kCheckTransaction) {
+    DCHECK_EQ(kTransactionActive, Runtime::Current()->IsActiveTransaction());
+  }
+  if (kTransactionActive) {
+    Runtime::Current()->RecordWriteFieldReference(this, field_offset,
+                                                  GetFieldObject<Object>(field_offset, is_volatile),
+                                                  true);
+  }
   if (this_is_valid) {
     VerifyObject(this);
   }
@@ -349,16 +405,26 @@
   }
 }
 
+template<bool kTransactionActive, bool kCheckTransaction>
 inline void Object::SetFieldObject(MemberOffset field_offset, Object* new_value, bool is_volatile,
                                    bool this_is_valid) {
-  SetFieldObjectWithoutWriteBarrier(field_offset, new_value, is_volatile, this_is_valid);
+  SetFieldObjectWithoutWriteBarrier<kTransactionActive, kCheckTransaction>(field_offset, new_value,
+                                                                           is_volatile,
+                                                                           this_is_valid);
   if (new_value != nullptr) {
     CheckFieldAssignment(field_offset, new_value);
     Runtime::Current()->GetHeap()->WriteBarrierField(this, field_offset, new_value);
   }
 }
 
+template<bool kTransactionActive, bool kCheckTransaction>
 inline bool Object::CasFieldObject(MemberOffset field_offset, Object* old_value, Object* new_value) {
+  if (kCheckTransaction) {
+    DCHECK_EQ(kTransactionActive, Runtime::Current()->IsActiveTransaction());
+  }
+  if (kTransactionActive) {
+    Runtime::Current()->RecordWriteFieldReference(this, field_offset, old_value, true);
+  }
   VerifyObject(this);
   byte* raw_addr = reinterpret_cast<byte*>(this) + field_offset.Int32Value();
   volatile int32_t* addr = reinterpret_cast<volatile int32_t*>(raw_addr);
diff --git a/runtime/mirror/object.h b/runtime/mirror/object.h
index 5874976..eb118c7 100644
--- a/runtime/mirror/object.h
+++ b/runtime/mirror/object.h
@@ -23,6 +23,7 @@
 #include "cutils/atomic-inline.h"
 #include "object_reference.h"
 #include "offsets.h"
+#include "runtime.h"
 
 namespace art {
 
@@ -130,6 +131,9 @@
   IntArray* AsIntArray() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
   LongArray* AsLongArray() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
+  FloatArray* AsFloatArray() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+  DoubleArray* AsDoubleArray() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
   String* AsString() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
   Throwable* AsThrowable() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
@@ -155,12 +159,15 @@
   // Accessor for Java type fields.
   template<class T> T* GetFieldObject(MemberOffset field_offset, bool is_volatile)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+  template<bool kTransactionActive, bool kCheckTransaction = true>
   void SetFieldObjectWithoutWriteBarrier(MemberOffset field_offset, Object* new_value,
                                          bool is_volatile, bool this_is_valid = true)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+  template<bool kTransactionActive, bool kCheckTransaction = true>
   void SetFieldObject(MemberOffset field_offset, Object* new_value, bool is_volatile,
                       bool this_is_valid = true)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+  template<bool kTransactionActive, bool kCheckTransaction = true>
   bool CasFieldObject(MemberOffset field_offset, Object* old_value, Object* new_value)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
@@ -172,27 +179,35 @@
 
   int32_t GetField32(MemberOffset field_offset, bool is_volatile);
 
+  template<bool kTransactionActive, bool kCheckTransaction = true>
   void SetField32(MemberOffset field_offset, int32_t new_value, bool is_volatile,
                   bool this_is_valid = true);
 
+  template<bool kTransactionActive, bool kCheckTransaction = true>
   bool CasField32(MemberOffset field_offset, int32_t old_value, int32_t new_value)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
   int64_t GetField64(MemberOffset field_offset, bool is_volatile);
 
+  template<bool kTransactionActive, bool kCheckTransaction = true>
   void SetField64(MemberOffset field_offset, int64_t new_value, bool is_volatile,
                   bool this_is_valid = true);
 
+  template<bool kTransactionActive, bool kCheckTransaction = true>
   bool CasField64(MemberOffset field_offset, int64_t old_value, int64_t new_value)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
-  template<typename T>
+  template<bool kTransactionActive, bool kCheckTransaction = true, typename T>
   void SetFieldPtr(MemberOffset field_offset, T new_value, bool is_volatile,
                    bool this_is_valid = true) {
 #ifndef __LP64__
-    SetField32(field_offset, reinterpret_cast<int32_t>(new_value), is_volatile, this_is_valid);
+    SetField32<kTransactionActive, kCheckTransaction>(field_offset,
+                                                      reinterpret_cast<int32_t>(new_value),
+                                                      is_volatile, this_is_valid);
 #else
-    SetField64(field_offset, reinterpret_cast<int64_t>(new_value), is_volatile, this_is_valid);
+    SetField64<kTransactionActive, kCheckTransaction>(field_offset,
+                                                      reinterpret_cast<int64_t>(new_value),
+                                                      is_volatile, this_is_valid);
 #endif
   }
 
diff --git a/runtime/mirror/object_array-inl.h b/runtime/mirror/object_array-inl.h
index c342479..521b6ce 100644
--- a/runtime/mirror/object_array-inl.h
+++ b/runtime/mirror/object_array-inl.h
@@ -72,26 +72,39 @@
 
 template<class T>
 inline void ObjectArray<T>::Set(int32_t i, T* object) {
+  if (Runtime::Current()->IsActiveTransaction()) {
+    Set<true>(i, object);
+  } else {
+    Set<false>(i, object);
+  }
+}
+
+template<class T>
+template<bool kTransactionActive, bool kCheckTransaction>
+inline void ObjectArray<T>::Set(int32_t i, T* object) {
   if (LIKELY(CheckIsValidIndex(i) && CheckAssignable(object))) {
-    SetFieldObject(OffsetOfElement(i), object, false);
+    SetFieldObject<kTransactionActive, kCheckTransaction>(OffsetOfElement(i), object, false);
   } else {
     DCHECK(Thread::Current()->IsExceptionPending());
   }
 }
 
 template<class T>
+template<bool kTransactionActive, bool kCheckTransaction>
 inline void ObjectArray<T>::SetWithoutChecks(int32_t i, T* object) {
   DCHECK(CheckIsValidIndex(i));
   DCHECK(CheckAssignable(object));
-  SetFieldObject(OffsetOfElement(i), object, false);
+  SetFieldObject<kTransactionActive, kCheckTransaction>(OffsetOfElement(i), object, false);
 }
 
 template<class T>
+template<bool kTransactionActive, bool kCheckTransaction>
 inline void ObjectArray<T>::SetWithoutChecksAndWriteBarrier(int32_t i, T* object) {
   DCHECK(CheckIsValidIndex(i));
   // TODO:  enable this check. It fails when writing the image in ImageWriter::FixupObjectArray.
   // DCHECK(CheckAssignable(object));
-  SetFieldObjectWithoutWriteBarrier(OffsetOfElement(i), object, false);
+  SetFieldObjectWithoutWriteBarrier<kTransactionActive, kCheckTransaction>(OffsetOfElement(i),
+                                                                           object, false);
 }
 
 template<class T>
@@ -164,15 +177,15 @@
     o = src->GetWithoutChecks(src_pos + i);
     if (o == nullptr) {
       // Null is always assignable.
-      SetWithoutChecks(dst_pos + i, nullptr);
+      SetWithoutChecks<false>(dst_pos + i, nullptr);
     } else {
       // TODO: use the underlying class reference to avoid uncompression when not necessary.
       Class* o_class = o->GetClass();
       if (LIKELY(lastAssignableElementClass == o_class)) {
-        SetWithoutChecks(dst_pos + i, o);
+        SetWithoutChecks<false>(dst_pos + i, o);
       } else if (LIKELY(dst_class->IsAssignableFrom(o_class))) {
         lastAssignableElementClass = o_class;
-        SetWithoutChecks(dst_pos + i, o);
+        SetWithoutChecks<false>(dst_pos + i, o);
       } else {
         // Can't put this element into the array, break to perform write-barrier and throw
         // exception.
diff --git a/runtime/mirror/object_array.h b/runtime/mirror/object_array.h
index 347494e..668b276 100644
--- a/runtime/mirror/object_array.h
+++ b/runtime/mirror/object_array.h
@@ -40,12 +40,20 @@
   bool CheckAssignable(T* object) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
   void Set(int32_t i, T* object) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+  // TODO fix thread safety analysis: should be SHARED_LOCKS_REQUIRED(Locks::mutator_lock_).
+  template<bool kTransactionActive, bool kCheckTransaction = true>
+  void Set(int32_t i, T* object) NO_THREAD_SAFETY_ANALYSIS;
 
   // Set element without bound and element type checks, to be used in limited
-  // circumstances, such as during boot image writing
-  void SetWithoutChecks(int32_t i, T* object) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
-  void SetWithoutChecksAndWriteBarrier(int32_t i, T* object)
-      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+  // circumstances, such as during boot image writing.
+  // TODO fix thread safety analysis broken by the use of template. This should be
+  // SHARED_LOCKS_REQUIRED(Locks::mutator_lock_).
+  template<bool kTransactionActive, bool kCheckTransaction = true>
+  void SetWithoutChecks(int32_t i, T* object) NO_THREAD_SAFETY_ANALYSIS;
+  // TODO fix thread safety analysis broken by the use of template. This should be
+  // SHARED_LOCKS_REQUIRED(Locks::mutator_lock_).
+  template<bool kTransactionActive, bool kCheckTransaction = true>
+  void SetWithoutChecksAndWriteBarrier(int32_t i, T* object) NO_THREAD_SAFETY_ANALYSIS;
 
   T* GetWithoutChecks(int32_t i) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
diff --git a/runtime/mirror/object_test.cc b/runtime/mirror/object_test.cc
index db9723b..40c3748 100644
--- a/runtime/mirror/object_test.cc
+++ b/runtime/mirror/object_test.cc
@@ -116,10 +116,10 @@
   EXPECT_EQ(2, oa->GetLength());
   EXPECT_TRUE(oa->Get(0) == NULL);
   EXPECT_TRUE(oa->Get(1) == NULL);
-  oa->Set(0, oa.get());
+  oa->Set<false>(0, oa.get());
   EXPECT_TRUE(oa->Get(0) == oa.get());
   EXPECT_TRUE(oa->Get(1) == NULL);
-  oa->Set(1, oa.get());
+  oa->Set<false>(1, oa.get());
   EXPECT_TRUE(oa->Get(0) == oa.get());
   EXPECT_TRUE(oa->Get(1) == oa.get());
 
@@ -235,12 +235,12 @@
 
   SirtRef<Class> c(soa.Self(), class_linker_->FindSystemClass("I"));
   SirtRef<IntArray> dims(soa.Self(), IntArray::Alloc(soa.Self(), 1));
-  dims->Set(0, 1);
+  dims->Set<false>(0, 1);
   Array* multi = Array::CreateMultiArray(soa.Self(), c, dims);
   EXPECT_TRUE(multi->GetClass() == class_linker_->FindSystemClass("[I"));
   EXPECT_EQ(1, multi->GetLength());
 
-  dims->Set(0, -1);
+  dims->Set<false>(0, -1);
   multi = Array::CreateMultiArray(soa.Self(), c, dims);
   EXPECT_TRUE(soa.Self()->IsExceptionPending());
   EXPECT_EQ(PrettyDescriptor(soa.Self()->GetException(NULL)->GetClass()),
@@ -250,8 +250,8 @@
   dims.reset(IntArray::Alloc(soa.Self(), 2));
   for (int i = 1; i < 20; ++i) {
     for (int j = 0; j < 20; ++j) {
-      dims->Set(0, i);
-      dims->Set(1, j);
+      dims->Set<false>(0, i);
+      dims->Set<false>(1, j);
       multi = Array::CreateMultiArray(soa.Self(), c, dims);
       EXPECT_TRUE(multi->GetClass() == class_linker_->FindSystemClass("[[I"));
       EXPECT_EQ(i, multi->GetLength());
@@ -301,10 +301,10 @@
   EXPECT_TRUE(s0 != NULL);
 
   SirtRef<CharArray> char_array(soa.Self(), CharArray::Alloc(soa.Self(), 0));
-  field->SetObj(field->GetDeclaringClass(), char_array.get());
+  field->SetObj<false>(field->GetDeclaringClass(), char_array.get());
   EXPECT_EQ(char_array.get(), field->GetObj(klass));
 
-  field->SetObj(field->GetDeclaringClass(), NULL);
+  field->SetObj<false>(field->GetDeclaringClass(), NULL);
   EXPECT_EQ(NULL, field->GetObj(klass));
 
   // TODO: more exhaustive tests of all 6 cases of ArtField::*FromCode
@@ -387,8 +387,8 @@
   EXPECT_EQ(string->GetLength(), 7);
   EXPECT_EQ(string->GetUtfLength(), 7);
 
-  string->SetOffset(2);
-  string->SetCount(5);
+  string->SetOffset<false>(2);
+  string->SetCount<false>(5);
   EXPECT_TRUE(string->Equals("droid"));
   EXPECT_EQ(string->GetLength(), 5);
   EXPECT_EQ(string->GetUtfLength(), 5);
diff --git a/runtime/mirror/stack_trace_element.cc b/runtime/mirror/stack_trace_element.cc
index 2e33198..6bc695d 100644
--- a/runtime/mirror/stack_trace_element.cc
+++ b/runtime/mirror/stack_trace_element.cc
@@ -46,18 +46,28 @@
   StackTraceElement* trace =
       down_cast<StackTraceElement*>(GetStackTraceElement()->AllocObject(self));
   if (LIKELY(trace != NULL)) {
-    trace->SetFieldObject(OFFSET_OF_OBJECT_MEMBER(StackTraceElement, declaring_class_),
-                          declaring_class.get(), false);
-    trace->SetFieldObject(OFFSET_OF_OBJECT_MEMBER(StackTraceElement, method_name_),
-                          method_name.get(), false);
-    trace->SetFieldObject(OFFSET_OF_OBJECT_MEMBER(StackTraceElement, file_name_),
-                          file_name.get(), false);
-    trace->SetField32(OFFSET_OF_OBJECT_MEMBER(StackTraceElement, line_number_),
-                      line_number, false);
+    if (Runtime::Current()->IsActiveTransaction()) {
+      trace->Init<true>(declaring_class, method_name, file_name, line_number);
+    } else {
+      trace->Init<false>(declaring_class, method_name, file_name, line_number);
+    }
   }
   return trace;
 }
 
+template<bool kTransactionActive>
+void StackTraceElement::Init(SirtRef<String>& declaring_class, SirtRef<String>& method_name,
+                             SirtRef<String>& file_name, int32_t line_number) {
+  SetFieldObject<kTransactionActive>(OFFSET_OF_OBJECT_MEMBER(StackTraceElement, declaring_class_),
+                                     declaring_class.get(), false);
+  SetFieldObject<kTransactionActive>(OFFSET_OF_OBJECT_MEMBER(StackTraceElement, method_name_),
+                                     method_name.get(), false);
+  SetFieldObject<kTransactionActive>(OFFSET_OF_OBJECT_MEMBER(StackTraceElement, file_name_),
+                                     file_name.get(), false);
+  SetField32<kTransactionActive>(OFFSET_OF_OBJECT_MEMBER(StackTraceElement, line_number_),
+                                 line_number, false);
+}
+
 void StackTraceElement::VisitRoots(RootCallback* callback, void* arg) {
   if (java_lang_StackTraceElement_ != nullptr) {
     java_lang_StackTraceElement_ = down_cast<Class*>(
diff --git a/runtime/mirror/stack_trace_element.h b/runtime/mirror/stack_trace_element.h
index 51817f6..779ec4b 100644
--- a/runtime/mirror/stack_trace_element.h
+++ b/runtime/mirror/stack_trace_element.h
@@ -67,6 +67,11 @@
   HeapReference<String> method_name_;
   int32_t line_number_;
 
+  template<bool kTransactionActive>
+  void Init(SirtRef<String>& declaring_class, SirtRef<String>& method_name,
+            SirtRef<String>& file_name, int32_t line_number)
+      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
   static Class* GetStackTraceElement() {
     DCHECK(java_lang_StackTraceElement_ != NULL);
     return java_lang_StackTraceElement_;
diff --git a/runtime/mirror/string.cc b/runtime/mirror/string.cc
index 6f4ead9..cd63c39 100644
--- a/runtime/mirror/string.cc
+++ b/runtime/mirror/string.cc
@@ -33,7 +33,7 @@
   return GetFieldObject<CharArray>(ValueOffset(), false);
 }
 
-void String::ComputeHashCode() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+void String::ComputeHashCode() {
   SetHashCode(ComputeUtf16Hash(GetCharArray(), GetOffset(), GetLength()));
 }
 
@@ -59,9 +59,10 @@
   return -1;
 }
 
-void String::SetArray(CharArray* new_array) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+template<bool kTransactionActive>
+void String::SetArray(CharArray* new_array) {
   DCHECK(new_array != NULL);
-  SetFieldObject(OFFSET_OF_OBJECT_MEMBER(String, array_), new_array, false);
+  SetFieldObject<kTransactionActive>(OFFSET_OF_OBJECT_MEMBER(String, array_), new_array, false);
 }
 
 // TODO: get global references for these
@@ -169,8 +170,13 @@
   // Hold reference in case AllocObject causes GC.
   String* string = down_cast<String*>(GetJavaLangString()->AllocObject(self));
   if (LIKELY(string != nullptr)) {
-    string->SetArray(array.get());
-    string->SetCount(array->GetLength());
+    if (Runtime::Current()->IsActiveTransaction()) {
+      string->SetArray<true>(array.get());
+      string->SetCount<true>(array->GetLength());
+    } else {
+      string->SetArray<false>(array.get());
+      string->SetCount<false>(array->GetLength());
+    }
   }
   return string;
 }
diff --git a/runtime/mirror/string.h b/runtime/mirror/string.h
index 57ec314..1340e7d 100644
--- a/runtime/mirror/string.h
+++ b/runtime/mirror/string.h
@@ -112,19 +112,23 @@
 
  private:
   void SetHashCode(int32_t new_hash_code) {
+    // Hash code is invariant so use non-transactional mode. Also disable check as we may run inside
+    // a transaction.
     DCHECK_EQ(0, GetField32(OFFSET_OF_OBJECT_MEMBER(String, hash_code_), false));
-    SetField32(OFFSET_OF_OBJECT_MEMBER(String, hash_code_), new_hash_code, false);
+    SetField32<false, false>(OFFSET_OF_OBJECT_MEMBER(String, hash_code_), new_hash_code, false);
   }
 
+  template<bool kTransactionActive>
   void SetCount(int32_t new_count) {
     DCHECK_LE(0, new_count);
-    SetField32(OFFSET_OF_OBJECT_MEMBER(String, count_), new_count, false);
+    SetField32<kTransactionActive>(OFFSET_OF_OBJECT_MEMBER(String, count_), new_count, false);
   }
 
+  template<bool kTransactionActive>
   void SetOffset(int32_t new_offset) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     DCHECK_LE(0, new_offset);
     DCHECK_GE(GetLength(), new_offset);
-    SetField32(OFFSET_OF_OBJECT_MEMBER(String, offset_), new_offset, false);
+    SetField32<kTransactionActive>(OFFSET_OF_OBJECT_MEMBER(String, offset_), new_offset, false);
   }
 
   static String* Alloc(Thread* self, int32_t utf16_length)
@@ -133,6 +137,7 @@
   static String* Alloc(Thread* self, const SirtRef<CharArray>& array)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
+  template<bool kTransactionActive>
   void SetArray(CharArray* new_array) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
   // Field order required by test "ValidateFieldOrderOfJavaCppUnionClasses".
diff --git a/runtime/mirror/throwable.cc b/runtime/mirror/throwable.cc
index a57bd43..fef7d36 100644
--- a/runtime/mirror/throwable.cc
+++ b/runtime/mirror/throwable.cc
@@ -38,7 +38,11 @@
   Throwable* current_cause = GetFieldObject<Throwable>(OFFSET_OF_OBJECT_MEMBER(Throwable, cause_),
                                                        false);
   CHECK(current_cause == NULL || current_cause == this);
-  SetFieldObject(OFFSET_OF_OBJECT_MEMBER(Throwable, cause_), cause, false);
+  if (Runtime::Current()->IsActiveTransaction()) {
+    SetFieldObject<true>(OFFSET_OF_OBJECT_MEMBER(Throwable, cause_), cause, false);
+  } else {
+    SetFieldObject<false>(OFFSET_OF_OBJECT_MEMBER(Throwable, cause_), cause, false);
+  }
 }
 
 bool Throwable::IsCheckedException() {
diff --git a/runtime/mirror/throwable.h b/runtime/mirror/throwable.h
index de71957..c1438d7 100644
--- a/runtime/mirror/throwable.h
+++ b/runtime/mirror/throwable.h
@@ -31,7 +31,13 @@
 class MANAGED Throwable : public Object {
  public:
   void SetDetailMessage(String* new_detail_message) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
-    SetFieldObject(OFFSET_OF_OBJECT_MEMBER(Throwable, detail_message_), new_detail_message, false);
+    if (Runtime::Current()->IsActiveTransaction()) {
+      SetFieldObject<true>(OFFSET_OF_OBJECT_MEMBER(Throwable, detail_message_), new_detail_message,
+                           false);
+    } else {
+      SetFieldObject<false>(OFFSET_OF_OBJECT_MEMBER(Throwable, detail_message_), new_detail_message,
+                            false);
+    }
   }
   String* GetDetailMessage() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     return GetFieldObject<String>(OFFSET_OF_OBJECT_MEMBER(Throwable, detail_message_), false);
diff --git a/runtime/native/java_lang_reflect_Field.cc b/runtime/native/java_lang_reflect_Field.cc
index 269a4a3..40aebfa 100644
--- a/runtime/native/java_lang_reflect_Field.cc
+++ b/runtime/native/java_lang_reflect_Field.cc
@@ -183,32 +183,32 @@
   o = sirt_obj.get();
   switch (FieldHelper(f).GetTypeAsPrimitiveType()) {
   case Primitive::kPrimBoolean:
-    f->SetBoolean(o, new_value.GetZ());
+    f->SetBoolean<false>(o, new_value.GetZ());
     break;
   case Primitive::kPrimByte:
-    f->SetByte(o, new_value.GetB());
+    f->SetByte<false>(o, new_value.GetB());
     break;
   case Primitive::kPrimChar:
-    f->SetChar(o, new_value.GetC());
+    f->SetChar<false>(o, new_value.GetC());
     break;
   case Primitive::kPrimDouble:
-    f->SetDouble(o, new_value.GetD());
+    f->SetDouble<false>(o, new_value.GetD());
     break;
   case Primitive::kPrimFloat:
-    f->SetFloat(o, new_value.GetF());
+    f->SetFloat<false>(o, new_value.GetF());
     break;
   case Primitive::kPrimInt:
-    f->SetInt(o, new_value.GetI());
+    f->SetInt<false>(o, new_value.GetI());
     break;
   case Primitive::kPrimLong:
-    f->SetLong(o, new_value.GetJ());
+    f->SetLong<false>(o, new_value.GetJ());
     break;
   case Primitive::kPrimShort:
-    f->SetShort(o, new_value.GetS());
+    f->SetShort<false>(o, new_value.GetS());
     break;
   case Primitive::kPrimNot:
     if (allow_references) {
-      f->SetObject(o, new_value.GetL());
+      f->SetObject<false>(o, new_value.GetL());
       break;
     }
     // Else fall through to report an error.
diff --git a/runtime/native/sun_misc_Unsafe.cc b/runtime/native/sun_misc_Unsafe.cc
index 6727862..ad0f317 100644
--- a/runtime/native/sun_misc_Unsafe.cc
+++ b/runtime/native/sun_misc_Unsafe.cc
@@ -27,7 +27,8 @@
                                          jint expectedValue, jint newValue) {
   ScopedFastNativeObjectAccess soa(env);
   mirror::Object* obj = soa.Decode<mirror::Object*>(javaObj);
-  bool success = obj->CasField32(MemberOffset(offset), expectedValue, newValue);
+  // JNI must use non transactional mode.
+  bool success = obj->CasField32<false>(MemberOffset(offset), expectedValue, newValue);
   return success ? JNI_TRUE : JNI_FALSE;
 }
 
@@ -35,7 +36,8 @@
                                           jlong expectedValue, jlong newValue) {
   ScopedFastNativeObjectAccess soa(env);
   mirror::Object* obj = soa.Decode<mirror::Object*>(javaObj);
-  bool success = obj->CasField64(MemberOffset(offset), expectedValue, newValue);
+  // JNI must use non transactional mode.
+  bool success = obj->CasField64<false>(MemberOffset(offset), expectedValue, newValue);
   return success ? JNI_TRUE : JNI_FALSE;
 }
 
@@ -45,7 +47,8 @@
   mirror::Object* obj = soa.Decode<mirror::Object*>(javaObj);
   mirror::Object* expectedValue = soa.Decode<mirror::Object*>(javaExpectedValue);
   mirror::Object* newValue = soa.Decode<mirror::Object*>(javaNewValue);
-  bool success = obj->CasFieldObject(MemberOffset(offset), expectedValue, newValue);
+  // JNI must use non transactional mode.
+  bool success = obj->CasFieldObject<false>(MemberOffset(offset), expectedValue, newValue);
   return success ? JNI_TRUE : JNI_FALSE;
 }
 
@@ -64,14 +67,16 @@
 static void Unsafe_putInt(JNIEnv* env, jobject, jobject javaObj, jlong offset, jint newValue) {
   ScopedFastNativeObjectAccess soa(env);
   mirror::Object* obj = soa.Decode<mirror::Object*>(javaObj);
-  obj->SetField32(MemberOffset(offset), newValue, false);
+  // JNI must use non transactional mode.
+  obj->SetField32<false>(MemberOffset(offset), newValue, false);
 }
 
 static void Unsafe_putIntVolatile(JNIEnv* env, jobject, jobject javaObj, jlong offset,
                                   jint newValue) {
   ScopedFastNativeObjectAccess soa(env);
   mirror::Object* obj = soa.Decode<mirror::Object*>(javaObj);
-  obj->SetField32(MemberOffset(offset), newValue, true);
+  // JNI must use non transactional mode.
+  obj->SetField32<false>(MemberOffset(offset), newValue, true);
 }
 
 static void Unsafe_putOrderedInt(JNIEnv* env, jobject, jobject javaObj, jlong offset,
@@ -79,7 +84,8 @@
   ScopedFastNativeObjectAccess soa(env);
   mirror::Object* obj = soa.Decode<mirror::Object*>(javaObj);
   QuasiAtomic::MembarStoreStore();
-  obj->SetField32(MemberOffset(offset), newValue, false);
+  // JNI must use non transactional mode.
+  obj->SetField32<false>(MemberOffset(offset), newValue, false);
 }
 
 static jlong Unsafe_getLong(JNIEnv* env, jobject, jobject javaObj, jlong offset) {
@@ -97,14 +103,16 @@
 static void Unsafe_putLong(JNIEnv* env, jobject, jobject javaObj, jlong offset, jlong newValue) {
   ScopedFastNativeObjectAccess soa(env);
   mirror::Object* obj = soa.Decode<mirror::Object*>(javaObj);
-  obj->SetField64(MemberOffset(offset), newValue, false);
+  // JNI must use non transactional mode.
+  obj->SetField64<false>(MemberOffset(offset), newValue, false);
 }
 
 static void Unsafe_putLongVolatile(JNIEnv* env, jobject, jobject javaObj, jlong offset,
                                    jlong newValue) {
   ScopedFastNativeObjectAccess soa(env);
   mirror::Object* obj = soa.Decode<mirror::Object*>(javaObj);
-  obj->SetField64(MemberOffset(offset), newValue, true);
+  // JNI must use non transactional mode.
+  obj->SetField64<false>(MemberOffset(offset), newValue, true);
 }
 
 static void Unsafe_putOrderedLong(JNIEnv* env, jobject, jobject javaObj, jlong offset,
@@ -112,7 +120,8 @@
   ScopedFastNativeObjectAccess soa(env);
   mirror::Object* obj = soa.Decode<mirror::Object*>(javaObj);
   QuasiAtomic::MembarStoreStore();
-  obj->SetField64(MemberOffset(offset), newValue, false);
+  // JNI must use non transactional mode.
+  obj->SetField64<false>(MemberOffset(offset), newValue, false);
 }
 
 static jobject Unsafe_getObjectVolatile(JNIEnv* env, jobject, jobject javaObj, jlong offset) {
@@ -134,7 +143,8 @@
   ScopedFastNativeObjectAccess soa(env);
   mirror::Object* obj = soa.Decode<mirror::Object*>(javaObj);
   mirror::Object* newValue = soa.Decode<mirror::Object*>(javaNewValue);
-  obj->SetFieldObject(MemberOffset(offset), newValue, false);
+  // JNI must use non transactional mode.
+  obj->SetFieldObject<false>(MemberOffset(offset), newValue, false);
 }
 
 static void Unsafe_putObjectVolatile(JNIEnv* env, jobject, jobject javaObj, jlong offset,
@@ -142,7 +152,8 @@
   ScopedFastNativeObjectAccess soa(env);
   mirror::Object* obj = soa.Decode<mirror::Object*>(javaObj);
   mirror::Object* newValue = soa.Decode<mirror::Object*>(javaNewValue);
-  obj->SetFieldObject(MemberOffset(offset), newValue, true);
+  // JNI must use non transactional mode.
+  obj->SetFieldObject<false>(MemberOffset(offset), newValue, true);
 }
 
 static void Unsafe_putOrderedObject(JNIEnv* env, jobject, jobject javaObj, jlong offset,
@@ -151,7 +162,8 @@
   mirror::Object* obj = soa.Decode<mirror::Object*>(javaObj);
   mirror::Object* newValue = soa.Decode<mirror::Object*>(javaNewValue);
   QuasiAtomic::MembarStoreStore();
-  obj->SetFieldObject(MemberOffset(offset), newValue, false);
+  // JNI must use non transactional mode.
+  obj->SetFieldObject<false>(MemberOffset(offset), newValue, false);
 }
 
 static jint Unsafe_getArrayBaseOffsetForComponentType(JNIEnv* env, jclass, jobject component_class) {
diff --git a/runtime/runtime.cc b/runtime/runtime.cc
index 6ca45e8..e1b0ed4 100644
--- a/runtime/runtime.cc
+++ b/runtime/runtime.cc
@@ -60,6 +60,7 @@
 #include "thread.h"
 #include "thread_list.h"
 #include "trace.h"
+#include "transaction.h"
 #include "profiler.h"
 #include "UniquePtr.h"
 #include "verifier/method_verifier.h"
@@ -120,7 +121,8 @@
       main_thread_group_(nullptr),
       system_thread_group_(nullptr),
       system_class_loader_(nullptr),
-      dump_gc_performance_on_shutdown_(false) {
+      dump_gc_performance_on_shutdown_(false),
+      preinitialization_transaction(nullptr) {
   for (int i = 0; i < Runtime::kLastCalleeSaveType; i++) {
     callee_save_methods_[i] = nullptr;
   }
@@ -826,7 +828,8 @@
       thread_class->FindDeclaredInstanceField("contextClassLoader", "Ljava/lang/ClassLoader;");
   CHECK(contextClassLoader != NULL);
 
-  contextClassLoader->SetObject(soa.Self()->GetPeer(), class_loader.get());
+  // We can't run in a transaction yet.
+  contextClassLoader->SetObject<false>(soa.Self()->GetPeer(), class_loader.get());
 
   return env->NewGlobalRef(system_class_loader.get());
 }
@@ -1305,6 +1308,10 @@
                                    bool clean_dirty) {
   intern_table_->VisitRoots(callback, arg, only_dirty, clean_dirty);
   class_linker_->VisitRoots(callback, arg, only_dirty, clean_dirty);
+  // TODO: is it the right place ?
+  if (preinitialization_transaction != nullptr) {
+    preinitialization_transaction->VisitRoots(callback, arg);
+  }
 }
 
 void Runtime::VisitNonThreadRoots(RootCallback* callback, void* arg) {
@@ -1371,7 +1378,7 @@
   SirtRef<mirror::ObjectArray<mirror::ArtMethod> > imtable(self, cl->AllocArtMethodArray(self, 64));
   mirror::ArtMethod* imt_conflict_method = Runtime::Current()->GetImtConflictMethod();
   for (size_t i = 0; i < static_cast<size_t>(imtable->GetLength()); i++) {
-    imtable->Set(i, imt_conflict_method);
+    imtable->Set<false>(i, imt_conflict_method);
   }
   return imtable.get();
 }
@@ -1547,4 +1554,74 @@
   BackgroundMethodSamplingProfiler::Start(profile_period_s_, profile_duration_s_, appDir, profile_interval_us_,
       profile_backoff_coefficient_, startImmediately);
 }
+
+// Transaction support.
+// TODO move them to header file for inlining.
+bool Runtime::IsActiveTransaction() const {
+  return preinitialization_transaction != nullptr;
+}
+
+void Runtime::EnterTransactionMode(Transaction* transaction) {
+  DCHECK(IsCompiler());
+  DCHECK(transaction != nullptr);
+  DCHECK(!IsActiveTransaction());
+  preinitialization_transaction = transaction;
+}
+
+void Runtime::ExitTransactionMode() {
+  DCHECK(IsCompiler());
+  DCHECK(IsActiveTransaction());
+  preinitialization_transaction = nullptr;
+}
+
+void Runtime::RecordWriteField32(mirror::Object* obj, MemberOffset field_offset,
+                                 uint32_t value, bool is_volatile) const {
+  DCHECK(IsCompiler());
+  DCHECK(IsActiveTransaction());
+  preinitialization_transaction->RecordWriteField32(obj, field_offset, value, is_volatile);
+}
+
+void Runtime::RecordWriteField64(mirror::Object* obj, MemberOffset field_offset,
+                                 uint64_t value, bool is_volatile) const {
+  DCHECK(IsCompiler());
+  DCHECK(IsActiveTransaction());
+  preinitialization_transaction->RecordWriteField64(obj, field_offset, value, is_volatile);
+}
+
+void Runtime::RecordWriteFieldReference(mirror::Object* obj, MemberOffset field_offset,
+                                        mirror::Object* value, bool is_volatile) const {
+  DCHECK(IsCompiler());
+  DCHECK(IsActiveTransaction());
+  preinitialization_transaction->RecordWriteFieldReference(obj, field_offset, value, is_volatile);
+}
+
+void Runtime::RecordWriteArray(mirror::Array* array, size_t index, uint64_t value) const {
+  DCHECK(IsCompiler());
+  DCHECK(IsActiveTransaction());
+  preinitialization_transaction->RecordWriteArray(array, index, value);
+}
+
+void Runtime::RecordStrongStringInsertion(mirror::String* s, uint32_t hash_code) const {
+  DCHECK(IsCompiler());
+  DCHECK(IsActiveTransaction());
+  preinitialization_transaction->RecordStrongStringInsertion(s, hash_code);
+}
+
+void Runtime::RecordWeakStringInsertion(mirror::String* s, uint32_t hash_code) const {
+  DCHECK(IsCompiler());
+  DCHECK(IsActiveTransaction());
+  preinitialization_transaction->RecordWeakStringInsertion(s, hash_code);
+}
+
+void Runtime::RecordStrongStringRemoval(mirror::String* s, uint32_t hash_code) const {
+  DCHECK(IsCompiler());
+  DCHECK(IsActiveTransaction());
+  preinitialization_transaction->RecordStrongStringRemoval(s, hash_code);
+}
+
+void Runtime::RecordWeakStringRemoval(mirror::String* s, uint32_t hash_code) const {
+  DCHECK(IsCompiler());
+  DCHECK(IsActiveTransaction());
+  preinitialization_transaction->RecordWeakStringRemoval(s, hash_code);
+}
 }  // namespace art
diff --git a/runtime/runtime.h b/runtime/runtime.h
index 07f3d7d..159de2e 100644
--- a/runtime/runtime.h
+++ b/runtime/runtime.h
@@ -46,6 +46,7 @@
 namespace mirror {
   class ArtMethod;
   class ClassLoader;
+  class Array;
   template<class T> class ObjectArray;
   template<class T> class PrimitiveArray;
   typedef PrimitiveArray<int8_t> ByteArray;
@@ -65,6 +66,7 @@
 class SignalCatcher;
 class ThreadList;
 class Trace;
+class Transaction;
 
 class Runtime {
  public:
@@ -474,6 +476,27 @@
 
   void StartProfiler(const char *appDir, bool startImmediately = false);
 
+  // Transaction support.
+  bool IsActiveTransaction() const;
+  void EnterTransactionMode(Transaction* transaction);
+  void ExitTransactionMode();
+  void RecordWriteField32(mirror::Object* obj, MemberOffset field_offset, uint32_t value,
+                          bool is_volatile) const;
+  void RecordWriteField64(mirror::Object* obj, MemberOffset field_offset, uint64_t value,
+                          bool is_volatile) const;
+  void RecordWriteFieldReference(mirror::Object* obj, MemberOffset field_offset,
+                                 mirror::Object* value, bool is_volatile) const;
+  void RecordWriteArray(mirror::Array* array, size_t index, uint64_t value) const
+      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+  void RecordStrongStringInsertion(mirror::String* s, uint32_t hash_code) const
+      EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_);
+  void RecordWeakStringInsertion(mirror::String* s, uint32_t hash_code) const
+      EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_);
+  void RecordStrongStringRemoval(mirror::String* s, uint32_t hash_code) const
+      EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_);
+  void RecordWeakStringRemoval(mirror::String* s, uint32_t hash_code) const
+      EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_);
+
  private:
   static void InitPlatformSignalHandlers();
 
@@ -612,6 +635,9 @@
   // If true, then we dump the GC cumulative timings on shutdown.
   bool dump_gc_performance_on_shutdown_;
 
+  // Transaction used for pre-initializing classes at compilation time.
+  Transaction* preinitialization_transaction;
+
   DISALLOW_COPY_AND_ASSIGN(Runtime);
 };
 
diff --git a/runtime/thread.cc b/runtime/thread.cc
index 3382811..5728391 100644
--- a/runtime/thread.cc
+++ b/runtime/thread.cc
@@ -398,14 +398,11 @@
     // non-null value. However, because we can run without code
     // available (in the compiler, in tests), we manually assign the
     // fields the constructor should have set.
-    soa.DecodeField(WellKnownClasses::java_lang_Thread_daemon)->
-        SetBoolean(opeer_, thread_is_daemon);
-    soa.DecodeField(WellKnownClasses::java_lang_Thread_group)->
-        SetObject(opeer_, soa.Decode<mirror::Object*>(thread_group));
-    soa.DecodeField(WellKnownClasses::java_lang_Thread_name)->
-        SetObject(opeer_, soa.Decode<mirror::Object*>(thread_name.get()));
-    soa.DecodeField(WellKnownClasses::java_lang_Thread_priority)->
-        SetInt(opeer_, thread_priority);
+    if (runtime->IsActiveTransaction()) {
+      InitPeer<true>(soa, thread_is_daemon, thread_group, thread_name.get(), thread_priority);
+    } else {
+      InitPeer<false>(soa, thread_is_daemon, thread_group, thread_name.get(), thread_priority);
+    }
     peer_thread_name.reset(GetThreadName(soa));
   }
   // 'thread_name' may have been null, so don't trust 'peer_thread_name' to be non-null.
@@ -414,6 +411,19 @@
   }
 }
 
+template<bool kTransactionActive>
+void Thread::InitPeer(ScopedObjectAccess& soa, jboolean thread_is_daemon, jobject thread_group,
+                      jobject thread_name, jint thread_priority) {
+  soa.DecodeField(WellKnownClasses::java_lang_Thread_daemon)->
+      SetBoolean<kTransactionActive>(opeer_, thread_is_daemon);
+  soa.DecodeField(WellKnownClasses::java_lang_Thread_group)->
+      SetObject<kTransactionActive>(opeer_, soa.Decode<mirror::Object*>(thread_group));
+  soa.DecodeField(WellKnownClasses::java_lang_Thread_name)->
+      SetObject<kTransactionActive>(opeer_, soa.Decode<mirror::Object*>(thread_name));
+  soa.DecodeField(WellKnownClasses::java_lang_Thread_priority)->
+      SetInt<kTransactionActive>(opeer_, thread_priority);
+}
+
 void Thread::SetThreadName(const char* name) {
   name_->assign(name);
   ::art::SetThreadName(name);
@@ -1020,7 +1030,11 @@
     RemoveFromThreadGroup(soa);
 
     // this.nativePeer = 0;
-    soa.DecodeField(WellKnownClasses::java_lang_Thread_nativePeer)->SetLong(opeer_, 0);
+    if (Runtime::Current()->IsActiveTransaction()) {
+      soa.DecodeField(WellKnownClasses::java_lang_Thread_nativePeer)->SetLong<true>(opeer_, 0);
+    } else {
+      soa.DecodeField(WellKnownClasses::java_lang_Thread_nativePeer)->SetLong<false>(opeer_, 0);
+    }
     Dbg::PostThreadDeath(self);
 
     // Thread.join() is implemented as an Object.wait() on the Thread.lock object. Signal anyone
@@ -1309,7 +1323,8 @@
     }
     // Save PC trace in last element of method trace, also places it into the
     // object graph.
-    method_trace->Set(depth, dex_pc_trace);
+    // We are called from native: use non-transactional mode.
+    method_trace->Set<false>(depth, dex_pc_trace);
     // Set the Object*s and assert that no thread suspension is now possible.
     const char* last_no_suspend_cause =
         self_->StartAssertNoThreadSuspension("Building internal stack trace");
@@ -1337,8 +1352,14 @@
     if (m->IsRuntimeMethod()) {
       return true;  // Ignore runtime frames (in particular callee save).
     }
-    method_trace_->Set(count_, m);
-    dex_pc_trace_->Set(count_, m->IsProxyMethod() ? DexFile::kDexNoIndex : GetDexPc());
+    // TODO dedup this code.
+    if (Runtime::Current()->IsActiveTransaction()) {
+      method_trace_->Set<true>(count_, m);
+      dex_pc_trace_->Set<true>(count_, m->IsProxyMethod() ? DexFile::kDexNoIndex : GetDexPc());
+    } else {
+      method_trace_->Set<false>(count_, m);
+      dex_pc_trace_->Set<false>(count_, m->IsProxyMethod() ? DexFile::kDexNoIndex : GetDexPc());
+    }
     ++count_;
     return true;
   }
@@ -1461,7 +1482,8 @@
     if (obj == nullptr) {
       return nullptr;
     }
-    soa.Decode<mirror::ObjectArray<mirror::StackTraceElement>*>(result)->Set(i, obj);
+    // We are called from native: use non-transactional mode.
+    soa.Decode<mirror::ObjectArray<mirror::StackTraceElement>*>(result)->Set<false>(i, obj);
   }
   return result;
 }
diff --git a/runtime/thread.h b/runtime/thread.h
index 6c072ba..48912d1 100644
--- a/runtime/thread.h
+++ b/runtime/thread.h
@@ -591,6 +591,11 @@
 
   void CreatePeer(const char* name, bool as_daemon, jobject thread_group);
 
+  template<bool kTransactionActive>
+  void InitPeer(ScopedObjectAccess& soa, jboolean thread_is_daemon, jobject thread_group,
+                jobject thread_name, jint thread_priority)
+      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
   // Avoid use, callers should use SetState. Used only by SignalCatcher::HandleSigQuit, ~Thread and
   // Dbg::Disconnected.
   ThreadState SetStateUnsafe(ThreadState new_state) {
diff --git a/runtime/transaction.cc b/runtime/transaction.cc
new file mode 100644
index 0000000..6adcfec
--- /dev/null
+++ b/runtime/transaction.cc
@@ -0,0 +1,419 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "transaction.h"
+
+#include "base/stl_util.h"
+#include "base/logging.h"
+#include "gc/accounting/card_table-inl.h"
+#include "intern_table.h"
+#include "mirror/object-inl.h"
+#include "mirror/object_array-inl.h"
+
+#include <list>
+
+namespace art {
+
+// TODO: remove (only used for debugging purpose).
+static constexpr bool kEnableTransactionStats = false;
+
+Transaction::Transaction() : log_lock_("transaction log lock", kTransactionLogLock) {
+  CHECK(Runtime::Current()->IsCompiler());
+}
+
+Transaction::~Transaction() {
+  if (kEnableTransactionStats) {
+    MutexLock mu(Thread::Current(), log_lock_);
+    size_t objects_count = object_logs_.size();
+    size_t field_values_count = 0;
+    for (auto it : object_logs_) {
+      field_values_count += it.second.Size();
+    }
+    size_t array_count = array_logs_.size();
+    size_t array_values_count = 0;
+    for (auto it : array_logs_) {
+      array_values_count += it.second.Size();
+    }
+    size_t string_count = intern_string_logs_.size();
+    LOG(INFO) << "Transaction::~Transaction"
+              << ": objects_count=" << objects_count
+              << ", field_values_count=" << field_values_count
+              << ", array_count=" << array_count
+              << ", array_values_count=" << array_values_count
+              << ", string_count=" << string_count;
+  }
+}
+
+void Transaction::RecordWriteField32(mirror::Object* obj, MemberOffset field_offset, uint32_t value,
+                                     bool is_volatile) {
+  DCHECK(obj != nullptr);
+  MutexLock mu(Thread::Current(), log_lock_);
+  ObjectLog& object_log = object_logs_[obj];
+  object_log.Log32BitsValue(field_offset, value, is_volatile);
+}
+
+void Transaction::RecordWriteField64(mirror::Object* obj, MemberOffset field_offset, uint64_t value,
+                                     bool is_volatile) {
+  DCHECK(obj != nullptr);
+  MutexLock mu(Thread::Current(), log_lock_);
+  ObjectLog& object_log = object_logs_[obj];
+  object_log.Log64BitsValue(field_offset, value, is_volatile);
+}
+
+void Transaction::RecordWriteFieldReference(mirror::Object* obj, MemberOffset field_offset,
+                                            mirror::Object* value, bool is_volatile) {
+  DCHECK(obj != nullptr);
+  MutexLock mu(Thread::Current(), log_lock_);
+  ObjectLog& object_log = object_logs_[obj];
+  object_log.LogReferenceValue(field_offset, value, is_volatile);
+}
+
+void Transaction::RecordWriteArray(mirror::Array* array, size_t index, uint64_t value) {
+  DCHECK(array != nullptr);
+  DCHECK(array->IsArrayInstance());
+  MutexLock mu(Thread::Current(), log_lock_);
+  ArrayLog& array_log = array_logs_[array];
+  array_log.LogValue(index, value);
+}
+
+void Transaction::RecordStrongStringInsertion(mirror::String* s, uint32_t hash_code) {
+  DCHECK(s != nullptr);
+  InternStringLog log(s, hash_code, InternStringLog::kStrongString, InternStringLog::kInsert);
+  LogInternedString(log);
+}
+
+void Transaction::RecordWeakStringInsertion(mirror::String* s, uint32_t hash_code) {
+  DCHECK(s != nullptr);
+  InternStringLog log(s, hash_code, InternStringLog::kWeakString, InternStringLog::kInsert);
+  LogInternedString(log);
+}
+
+void Transaction::RecordStrongStringRemoval(mirror::String* s, uint32_t hash_code) {
+  InternStringLog log(s, hash_code, InternStringLog::kStrongString, InternStringLog::kRemove);
+  LogInternedString(log);
+}
+
+void Transaction::RecordWeakStringRemoval(mirror::String* s, uint32_t hash_code) {
+  InternStringLog log(s, hash_code, InternStringLog::kWeakString, InternStringLog::kRemove);
+  LogInternedString(log);
+}
+
+void Transaction::LogInternedString(InternStringLog& log) {
+  Locks::intern_table_lock_->AssertExclusiveHeld(Thread::Current());
+  MutexLock mu(Thread::Current(), log_lock_);
+  intern_string_logs_.push_front(log);
+}
+
+void Transaction::Abort() {
+  CHECK(!Runtime::Current()->IsActiveTransaction());
+  Thread* self = Thread::Current();
+  self->AssertNoPendingException();
+  MutexLock mu1(self, *Locks::intern_table_lock_);
+  MutexLock mu2(self, log_lock_);
+  UndoObjectModifications();
+  UndoArrayModifications();
+  UndoInternStringTableModifications();
+}
+
+void Transaction::UndoObjectModifications() {
+  // TODO we may not need to restore objects allocated during this transaction. Or we could directly
+  // remove them from the heap.
+  for (auto it : object_logs_) {
+    it.second.Undo(it.first);
+  }
+  object_logs_.clear();
+}
+
+void Transaction::UndoArrayModifications() {
+  // TODO we may not need to restore array allocated during this transaction. Or we could directly
+  // remove them from the heap.
+  for (auto it : array_logs_) {
+    it.second.Undo(it.first);
+  }
+  array_logs_.clear();
+}
+
+void Transaction::UndoInternStringTableModifications() {
+  InternTable* const intern_table = Runtime::Current()->GetInternTable();
+  // We want to undo each operation from the most recent to the oldest. List has been filled so the
+  // most recent operation is at list begin so just have to iterate over it.
+  for (InternStringLog& string_log : intern_string_logs_) {
+    string_log.Undo(intern_table);
+  }
+  intern_string_logs_.clear();
+}
+
+void Transaction::VisitRoots(RootCallback* callback, void* arg) {
+  LOG(INFO) << "Transaction::VisitRoots";
+  MutexLock mu(Thread::Current(), log_lock_);
+  VisitObjectLogs(callback, arg);
+  VisitArrayLogs(callback, arg);
+  VisitStringLogs(callback, arg);
+}
+
+void Transaction::VisitObjectLogs(RootCallback* callback, void* arg) {
+  // List of moving roots.
+  typedef std::pair<mirror::Object*, mirror::Object*> ObjectPair;
+  std::list<ObjectPair> moving_roots;
+
+  // Visit roots.
+  for (auto it : object_logs_) {
+    it.second.VisitRoots(callback, arg);
+    mirror::Object* old_root = it.first;
+    mirror::Object* new_root = callback(old_root, arg, 0, kRootUnknown);
+    if (new_root != old_root) {
+      moving_roots.push_back(std::make_pair(old_root, new_root));
+    }
+  }
+
+  // Update object logs with moving roots.
+  for (const ObjectPair& pair : moving_roots) {
+    mirror::Object* old_root = pair.first;
+    mirror::Object* new_root = pair.second;
+    auto old_root_it = object_logs_.find(old_root);
+    CHECK(old_root_it != object_logs_.end());
+    CHECK(object_logs_.find(new_root) == object_logs_.end());
+    object_logs_.insert(std::make_pair(new_root, old_root_it->second));
+    object_logs_.erase(old_root_it);
+  }
+}
+
+void Transaction::VisitArrayLogs(RootCallback* callback, void* arg) {
+  // List of moving roots.
+  typedef std::pair<mirror::Array*, mirror::Array*> ArrayPair;
+  std::list<ArrayPair> moving_roots;
+
+  for (auto it : array_logs_) {
+    mirror::Array* old_root = it.first;
+    if (old_root->IsObjectArray()) {
+      it.second.VisitRoots(callback, arg);
+    }
+    mirror::Array* new_root = down_cast<mirror::Array*>(callback(old_root, arg, 0, kRootUnknown));
+    if (new_root != old_root) {
+      moving_roots.push_back(std::make_pair(old_root, new_root));
+    }
+  }
+
+  // Update array logs with moving roots.
+  for (const ArrayPair& pair : moving_roots) {
+    mirror::Array* old_root = pair.first;
+    mirror::Array* new_root = pair.second;
+    auto old_root_it = array_logs_.find(old_root);
+    CHECK(old_root_it != array_logs_.end());
+    CHECK(array_logs_.find(new_root) == array_logs_.end());
+    array_logs_.insert(std::make_pair(new_root, old_root_it->second));
+    array_logs_.erase(old_root_it);
+  }
+}
+
+void Transaction::VisitStringLogs(RootCallback* callback, void* arg) {
+  for (InternStringLog& log : intern_string_logs_) {
+    log.VisitRoots(callback, arg);
+  }
+}
+
+void Transaction::ObjectLog::Log32BitsValue(MemberOffset offset, uint32_t value, bool is_volatile) {
+  auto it = field_values_.find(offset.Uint32Value());
+  if (it == field_values_.end()) {
+    ObjectLog::FieldValue field_value;
+    field_value.value = value;
+    field_value.is_volatile = is_volatile;
+    field_value.kind = ObjectLog::k32Bits;
+    field_values_.insert(std::make_pair(offset.Uint32Value(), field_value));
+  }
+}
+
+void Transaction::ObjectLog::Log64BitsValue(MemberOffset offset, uint64_t value, bool is_volatile) {
+  auto it = field_values_.find(offset.Uint32Value());
+  if (it == field_values_.end()) {
+    ObjectLog::FieldValue field_value;
+    field_value.value = value;
+    field_value.is_volatile = is_volatile;
+    field_value.kind = ObjectLog::k64Bits;
+    field_values_.insert(std::make_pair(offset.Uint32Value(), field_value));
+  }
+}
+
+void Transaction::ObjectLog::LogReferenceValue(MemberOffset offset, mirror::Object* obj, bool is_volatile) {
+  auto it = field_values_.find(offset.Uint32Value());
+  if (it == field_values_.end()) {
+    ObjectLog::FieldValue field_value;
+    field_value.value = reinterpret_cast<uintptr_t>(obj);
+    field_value.is_volatile = is_volatile;
+    field_value.kind = ObjectLog::kReference;
+    field_values_.insert(std::make_pair(offset.Uint32Value(), field_value));
+  }
+}
+
+void Transaction::ObjectLog::Undo(mirror::Object* obj) {
+  for (auto& it : field_values_) {
+    // Garbage collector needs to access object's class and array's length. So we don't rollback
+    // these values.
+    MemberOffset field_offset(it.first);
+    if (field_offset.Uint32Value() == mirror::Class::ClassOffset().Uint32Value()) {
+      // Skip Object::class field.
+      continue;
+    }
+    if (obj->IsArrayInstance() &&
+        field_offset.Uint32Value() == mirror::Array::LengthOffset().Uint32Value()) {
+      // Skip Array::length field.
+      continue;
+    }
+    FieldValue& field_value = it.second;
+    UndoFieldWrite(obj, field_offset, field_value);
+  }
+}
+
+void Transaction::ObjectLog::UndoFieldWrite(mirror::Object* obj, MemberOffset field_offset,
+                                            const FieldValue& field_value) {
+  // TODO We may want to abort a transaction while still being in transaction mode. In this case,
+  // we'd need to disable the check.
+  constexpr bool kCheckTransaction = true;
+  switch (field_value.kind) {
+    case k32Bits:
+      obj->SetField32<false, kCheckTransaction>(field_offset, static_cast<uint32_t>(field_value.value),
+                                                field_value.is_volatile);
+      break;
+    case k64Bits:
+      obj->SetField64<false, kCheckTransaction>(field_offset, field_value.value,
+                                                field_value.is_volatile);
+      break;
+    case kReference:
+      obj->SetFieldObject<false, kCheckTransaction>(field_offset,
+                                                    reinterpret_cast<mirror::Object*>(field_value.value),
+                                                    field_value.is_volatile);
+      break;
+    default:
+      LOG(FATAL) << "Unknown value kind " << field_value.kind;
+      break;
+  }
+}
+
+void Transaction::ObjectLog::VisitRoots(RootCallback* callback, void* arg) {
+  for (auto it : field_values_) {
+    FieldValue& field_value = it.second;
+    if (field_value.kind == ObjectLog::kReference) {
+      mirror::Object* obj = reinterpret_cast<mirror::Object*>(static_cast<uintptr_t>(field_value.value));
+      field_value.value = reinterpret_cast<uintptr_t>(callback(obj, arg, 0, kRootUnknown));
+    }
+  }
+}
+
+void Transaction::InternStringLog::Undo(InternTable* intern_table) {
+  DCHECK(intern_table != nullptr);
+  switch (string_op_) {
+      case InternStringLog::kInsert: {
+        switch (string_kind_) {
+          case InternStringLog::kStrongString:
+            intern_table->RemoveStrongFromTransaction(str_, hash_code_);
+            break;
+          case InternStringLog::kWeakString:
+            intern_table->RemoveWeakFromTransaction(str_, hash_code_);
+            break;
+          default:
+            LOG(FATAL) << "Unknown interned string kind";
+            break;
+        }
+        break;
+      }
+      case InternStringLog::kRemove: {
+        switch (string_kind_) {
+          case InternStringLog::kStrongString:
+            intern_table->InsertStrongFromTransaction(str_, hash_code_);
+            break;
+          case InternStringLog::kWeakString:
+            intern_table->InsertWeakFromTransaction(str_, hash_code_);
+            break;
+          default:
+            LOG(FATAL) << "Unknown interned string kind";
+            break;
+        }
+        break;
+      }
+      default:
+        LOG(FATAL) << "Unknown interned string op";
+        break;
+    }
+}
+
+void Transaction::InternStringLog::VisitRoots(RootCallback* callback, void* arg) {
+  str_ = down_cast<mirror::String*>(callback(str_, arg, 0, kRootInternedString));
+}
+
+void Transaction::ArrayLog::LogValue(size_t index, uint64_t value) {
+  auto it = array_values_.find(index);
+  if (it == array_values_.end()) {
+    array_values_.insert(std::make_pair(index, value));
+  }
+}
+
+void Transaction::ArrayLog::Undo(mirror::Array* array) {
+  DCHECK(array != nullptr);
+  DCHECK(array->IsArrayInstance());
+  Primitive::Type type = array->GetClass()->GetComponentType()->GetPrimitiveType();
+  for (auto it : array_values_) {
+    UndoArrayWrite(array, type, it.first, it.second);
+  }
+}
+
+void Transaction::ArrayLog::UndoArrayWrite(mirror::Array* array, Primitive::Type array_type,
+                                           size_t index, uint64_t value) {
+  // TODO We may want to abort a transaction while still being in transaction mode. In this case,
+  // we'd need to disable the check.
+  switch (array_type) {
+    case Primitive::kPrimBoolean:
+      array->AsBooleanArray()->SetWithoutChecks<false>(index, static_cast<uint8_t>(value));
+      break;
+    case Primitive::kPrimByte:
+      array->AsByteArray()->SetWithoutChecks<false>(index, static_cast<int8_t>(value));
+      break;
+    case Primitive::kPrimChar:
+      array->AsCharArray()->SetWithoutChecks<false>(index, static_cast<uint16_t>(value));
+      break;
+    case Primitive::kPrimShort:
+      array->AsShortArray()->SetWithoutChecks<false>(index, static_cast<int16_t>(value));
+      break;
+    case Primitive::kPrimInt:
+      array->AsIntArray()->SetWithoutChecks<false>(index, static_cast<int32_t>(value));
+      break;
+    case Primitive::kPrimFloat:
+      array->AsFloatArray()->SetWithoutChecks<false>(index, static_cast<float>(value));
+      break;
+    case Primitive::kPrimLong:
+      array->AsLongArray()->SetWithoutChecks<false>(index, static_cast<int64_t>(value));
+      break;
+    case Primitive::kPrimDouble:
+      array->AsDoubleArray()->SetWithoutChecks<false>(index, static_cast<double>(value));
+      break;
+    case Primitive::kPrimNot: {
+      mirror::ObjectArray<mirror::Object>* obj_array = array->AsObjectArray<mirror::Object>();
+      obj_array->SetWithoutChecks<false>(index, reinterpret_cast<mirror::Object*>(
+          static_cast<uintptr_t>(value)));
+      break;
+    }
+    default:
+      LOG(FATAL) << "Unsupported type " << array_type;
+  }
+}
+
+void Transaction::ArrayLog::VisitRoots(RootCallback* callback, void* arg) {
+  for (auto& it : array_values_) {
+    mirror::Object* obj = reinterpret_cast<mirror::Object*>(static_cast<uintptr_t>(it.second));
+    it.second = reinterpret_cast<uintptr_t>(callback(obj, arg, 0, kRootUnknown));
+  }
+}
+
+}  // namespace art
diff --git a/runtime/transaction.h b/runtime/transaction.h
new file mode 100644
index 0000000..68f9540
--- /dev/null
+++ b/runtime/transaction.h
@@ -0,0 +1,195 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ART_RUNTIME_TRANSACTION_H_
+#define ART_RUNTIME_TRANSACTION_H_
+
+#include "base/macros.h"
+#include "base/mutex.h"
+#include "locks.h"
+#include "offsets.h"
+#include "primitive.h"
+#include "object_callbacks.h"
+#include "safe_map.h"
+
+#include <list>
+#include <map>
+
+namespace art {
+namespace mirror {
+class Array;
+class Object;
+class String;
+}
+class InternTable;
+
+class Transaction {
+ public:
+  Transaction();
+  ~Transaction();
+
+  // Record object field changes.
+  void RecordWriteField32(mirror::Object* obj, MemberOffset field_offset, uint32_t value,
+                          bool is_volatile)
+      LOCKS_EXCLUDED(log_lock_);
+  void RecordWriteField64(mirror::Object* obj, MemberOffset field_offset, uint64_t value,
+                          bool is_volatile)
+      LOCKS_EXCLUDED(log_lock_);
+  void RecordWriteFieldReference(mirror::Object* obj, MemberOffset field_offset,
+                                 mirror::Object* value, bool is_volatile)
+      LOCKS_EXCLUDED(log_lock_);
+
+  // Record array change.
+  void RecordWriteArray(mirror::Array* array, size_t index, uint64_t value)
+      LOCKS_EXCLUDED(log_lock_)
+      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
+  // Record intern string table changes.
+  void RecordStrongStringInsertion(mirror::String* s, uint32_t hash_code)
+      EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_)
+      LOCKS_EXCLUDED(log_lock_);
+  void RecordWeakStringInsertion(mirror::String* s, uint32_t hash_code)
+      EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_)
+      LOCKS_EXCLUDED(log_lock_);
+  void RecordStrongStringRemoval(mirror::String* s, uint32_t hash_code)
+      EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_)
+      LOCKS_EXCLUDED(log_lock_);
+  void RecordWeakStringRemoval(mirror::String* s, uint32_t hash_code)
+      EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_)
+      LOCKS_EXCLUDED(log_lock_);
+
+  // Abort transaction by undoing all recorded changes.
+  void Abort()
+      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
+      LOCKS_EXCLUDED(log_lock_);
+
+  void VisitRoots(RootCallback* callback, void* arg)
+      LOCKS_EXCLUDED(log_lock_)
+      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
+ private:
+  class ObjectLog {
+   public:
+    void Log32BitsValue(MemberOffset offset, uint32_t value, bool is_volatile);
+    void Log64BitsValue(MemberOffset offset, uint64_t value, bool is_volatile);
+    void LogReferenceValue(MemberOffset offset, mirror::Object* obj, bool is_volatile);
+
+    void Undo(mirror::Object* obj) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+    void VisitRoots(RootCallback* callback, void* arg);
+
+    size_t Size() const {
+      return field_values_.size();
+    }
+
+   private:
+    enum FieldValueKind {
+      k32Bits,
+      k64Bits,
+      kReference
+    };
+    struct FieldValue {
+      // TODO use JValue instead ?
+      uint64_t value;
+      FieldValueKind kind;
+      bool is_volatile;
+    };
+
+    void UndoFieldWrite(mirror::Object* obj, MemberOffset field_offset,
+                        const FieldValue& field_value) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
+    // Maps field's offset to its value.
+    std::map<uint32_t, FieldValue> field_values_;
+  };
+
+  class ArrayLog {
+   public:
+    void LogValue(size_t index, uint64_t value);
+
+    void Undo(mirror::Array* obj) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+    void VisitRoots(RootCallback* callback, void* arg);
+
+    size_t Size() const {
+      return array_values_.size();
+    }
+
+   private:
+    void UndoArrayWrite(mirror::Array* array, Primitive::Type array_type, size_t index,
+                        uint64_t value) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
+    // Maps index to value.
+    // TODO use JValue instead ?
+    std::map<size_t, uint64_t> array_values_;
+  };
+
+  class InternStringLog {
+   public:
+    enum StringKind {
+      kStrongString,
+      kWeakString
+    };
+    enum StringOp {
+      kInsert,
+      kRemove
+    };
+    InternStringLog(mirror::String* s, uint32_t hash_code, StringKind kind, StringOp op)
+      : str_(s), hash_code_(hash_code), string_kind_(kind), string_op_(op) {
+    }
+
+    void Undo(InternTable* intern_table) EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_);
+    void VisitRoots(RootCallback* callback, void* arg);
+
+   private:
+    mirror::String* str_;
+    uint32_t hash_code_;
+    StringKind string_kind_;
+    StringOp string_op_;
+  };
+
+  void LogInternedString(InternStringLog& log)
+      EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_)
+      LOCKS_EXCLUDED(log_lock_);
+
+  void UndoObjectModifications()
+      EXCLUSIVE_LOCKS_REQUIRED(log_lock_)
+      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+  void UndoArrayModifications()
+      EXCLUSIVE_LOCKS_REQUIRED(log_lock_)
+      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+  void UndoInternStringTableModifications()
+      EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_)
+      EXCLUSIVE_LOCKS_REQUIRED(log_lock_);
+
+  void VisitObjectLogs(RootCallback* callback, void* arg)
+      EXCLUSIVE_LOCKS_REQUIRED(log_lock_)
+      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+  void VisitArrayLogs(RootCallback* callback, void* arg)
+      EXCLUSIVE_LOCKS_REQUIRED(log_lock_)
+      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+  void VisitStringLogs(RootCallback* callback, void* arg)
+      EXCLUSIVE_LOCKS_REQUIRED(log_lock_)
+      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
+  Mutex log_lock_ ACQUIRED_AFTER(Locks::intern_table_lock_);
+  std::map<mirror::Object*, ObjectLog> object_logs_ GUARDED_BY(log_lock_);
+  std::map<mirror::Array*, ArrayLog> array_logs_  GUARDED_BY(log_lock_);
+  std::list<InternStringLog> intern_string_logs_ GUARDED_BY(log_lock_);
+
+  DISALLOW_COPY_AND_ASSIGN(Transaction);
+};
+
+}  // namespace art
+
+#endif  // ART_RUNTIME_TRANSACTION_H_
diff --git a/runtime/transaction_test.cc b/runtime/transaction_test.cc
new file mode 100644
index 0000000..dcfa24b
--- /dev/null
+++ b/runtime/transaction_test.cc
@@ -0,0 +1,472 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "common_test.h"
+#include "invoke_arg_array_builder.h"
+#include "mirror/array-inl.h"
+#include "mirror/art_field-inl.h"
+#include "mirror/art_method-inl.h"
+#include "transaction.h"
+
+namespace art {
+
+class TransactionTest : public CommonTest {
+};
+
+TEST_F(TransactionTest, Object_class) {
+  ScopedObjectAccess soa(Thread::Current());
+  SirtRef<mirror::Class> sirt_klass(soa.Self(),
+                                    class_linker_->FindSystemClass("Ljava/lang/Object;"));
+  ASSERT_TRUE(sirt_klass.get() != nullptr);
+
+  Transaction transaction;
+  Runtime::Current()->EnterTransactionMode(&transaction);
+  SirtRef<mirror::Object> sirt_obj(soa.Self(), sirt_klass->AllocObject(soa.Self()));
+  ASSERT_TRUE(sirt_obj.get() != nullptr);
+  ASSERT_EQ(sirt_obj->GetClass(), sirt_klass.get());
+  Runtime::Current()->ExitTransactionMode();
+
+  // Aborting transaction must not clear the Object::class field.
+  transaction.Abort();
+  EXPECT_EQ(sirt_obj->GetClass(), sirt_klass.get());
+}
+
+TEST_F(TransactionTest, Object_monitor) {
+  ScopedObjectAccess soa(Thread::Current());
+  SirtRef<mirror::Class> sirt_klass(soa.Self(),
+                                    class_linker_->FindSystemClass("Ljava/lang/Object;"));
+  ASSERT_TRUE(sirt_klass.get() != nullptr);
+  SirtRef<mirror::Object> sirt_obj(soa.Self(), sirt_klass->AllocObject(soa.Self()));
+  ASSERT_TRUE(sirt_obj.get() != nullptr);
+  ASSERT_EQ(sirt_obj->GetClass(), sirt_klass.get());
+
+  // Lock object's monitor outside the transaction.
+  sirt_obj->MonitorEnter(soa.Self());
+  uint32_t old_lock_word = sirt_obj->GetLockWord().GetValue();
+
+  Transaction transaction;
+  Runtime::Current()->EnterTransactionMode(&transaction);
+  // Unlock object's monitor inside the transaction.
+  sirt_obj->MonitorExit(soa.Self());
+  uint32_t new_lock_word = sirt_obj->GetLockWord().GetValue();
+  Runtime::Current()->ExitTransactionMode();
+
+  // Aborting transaction must not clear the Object::class field.
+  transaction.Abort();
+  uint32_t aborted_lock_word = sirt_obj->GetLockWord().GetValue();
+  EXPECT_NE(old_lock_word, new_lock_word);
+  EXPECT_EQ(aborted_lock_word, new_lock_word);
+}
+
+TEST_F(TransactionTest, Array_length) {
+  ScopedObjectAccess soa(Thread::Current());
+  SirtRef<mirror::Class> sirt_klass(soa.Self(),
+                                    class_linker_->FindSystemClass("[Ljava/lang/Object;"));
+  ASSERT_TRUE(sirt_klass.get() != nullptr);
+
+  constexpr int32_t kArraySize = 2;
+
+  Transaction transaction;
+  Runtime::Current()->EnterTransactionMode(&transaction);
+
+  // Allocate an array during transaction.
+  SirtRef<mirror::Array> sirt_obj(soa.Self(),
+                                  mirror::Array::Alloc<false>(soa.Self(), sirt_klass.get(), kArraySize));
+  ASSERT_TRUE(sirt_obj.get() != nullptr);
+  ASSERT_EQ(sirt_obj->GetClass(), sirt_klass.get());
+  Runtime::Current()->ExitTransactionMode();
+
+  // Aborting transaction must not clear the Object::class field.
+  transaction.Abort();
+  EXPECT_EQ(sirt_obj->GetLength(), kArraySize);
+}
+
+TEST_F(TransactionTest, StaticFieldsTest) {
+  ScopedObjectAccess soa(Thread::Current());
+  SirtRef<mirror::ClassLoader> class_loader(
+      soa.Self(), soa.Decode<mirror::ClassLoader*>(LoadDex("Transaction")));
+  ASSERT_TRUE(class_loader.get() != nullptr);
+
+  SirtRef<mirror::Class> sirt_klass(soa.Self(),
+                                    class_linker_->FindClass("LStaticFieldsTest;", class_loader));
+  ASSERT_TRUE(sirt_klass.get() != nullptr);
+  class_linker_->EnsureInitialized(sirt_klass, true, true);
+  ASSERT_TRUE(sirt_klass->IsInitialized());
+
+  // Lookup fields.
+  mirror::ArtField* booleanField = sirt_klass->FindDeclaredStaticField("booleanField", "Z");
+  ASSERT_TRUE(booleanField != nullptr);
+  ASSERT_EQ(FieldHelper(booleanField).GetTypeAsPrimitiveType(), Primitive::kPrimBoolean);
+  ASSERT_EQ(booleanField->GetBoolean(sirt_klass.get()), false);
+
+  mirror::ArtField* byteField = sirt_klass->FindDeclaredStaticField("byteField", "B");
+  ASSERT_TRUE(byteField != nullptr);
+  ASSERT_EQ(FieldHelper(byteField).GetTypeAsPrimitiveType(), Primitive::kPrimByte);
+  ASSERT_EQ(byteField->GetByte(sirt_klass.get()), 0);
+
+  mirror::ArtField* charField = sirt_klass->FindDeclaredStaticField("charField", "C");
+  ASSERT_TRUE(charField != nullptr);
+  ASSERT_EQ(FieldHelper(charField).GetTypeAsPrimitiveType(), Primitive::kPrimChar);
+  ASSERT_EQ(charField->GetChar(sirt_klass.get()), 0u);
+
+  mirror::ArtField* shortField = sirt_klass->FindDeclaredStaticField("shortField", "S");
+  ASSERT_TRUE(shortField != nullptr);
+  ASSERT_EQ(FieldHelper(shortField).GetTypeAsPrimitiveType(), Primitive::kPrimShort);
+  ASSERT_EQ(shortField->GetShort(sirt_klass.get()), 0);
+
+  mirror::ArtField* intField = sirt_klass->FindDeclaredStaticField("intField", "I");
+  ASSERT_TRUE(intField != nullptr);
+  ASSERT_EQ(FieldHelper(intField).GetTypeAsPrimitiveType(), Primitive::kPrimInt);
+  ASSERT_EQ(intField->GetInt(sirt_klass.get()), 0);
+
+  mirror::ArtField* longField = sirt_klass->FindDeclaredStaticField("longField", "J");
+  ASSERT_TRUE(longField != nullptr);
+  ASSERT_EQ(FieldHelper(longField).GetTypeAsPrimitiveType(), Primitive::kPrimLong);
+  ASSERT_EQ(longField->GetLong(sirt_klass.get()), static_cast<int64_t>(0));
+
+  mirror::ArtField* floatField = sirt_klass->FindDeclaredStaticField("floatField", "F");
+  ASSERT_TRUE(floatField != nullptr);
+  ASSERT_EQ(FieldHelper(floatField).GetTypeAsPrimitiveType(), Primitive::kPrimFloat);
+  ASSERT_EQ(floatField->GetFloat(sirt_klass.get()), static_cast<float>(0.0f));
+
+  mirror::ArtField* doubleField = sirt_klass->FindDeclaredStaticField("doubleField", "D");
+  ASSERT_TRUE(doubleField != nullptr);
+  ASSERT_EQ(FieldHelper(doubleField).GetTypeAsPrimitiveType(), Primitive::kPrimDouble);
+  ASSERT_EQ(doubleField->GetDouble(sirt_klass.get()), static_cast<double>(0.0));
+
+  mirror::ArtField* objectField = sirt_klass->FindDeclaredStaticField("objectField", "Ljava/lang/Object;");
+  ASSERT_TRUE(objectField != nullptr);
+  ASSERT_EQ(FieldHelper(objectField).GetTypeAsPrimitiveType(), Primitive::kPrimNot);
+  ASSERT_EQ(objectField->GetObject(sirt_klass.get()), nullptr);
+
+  // Create a java.lang.Object instance to set objectField.
+  SirtRef<mirror::Class> object_klass(soa.Self(), class_linker_->FindSystemClass("Ljava/lang/Object;"));
+  ASSERT_TRUE(object_klass.get() != nullptr);
+  SirtRef<mirror::Object> sirt_obj(soa.Self(), sirt_klass->AllocObject(soa.Self()));
+  ASSERT_TRUE(sirt_obj.get() != nullptr);
+  ASSERT_EQ(sirt_obj->GetClass(), sirt_klass.get());
+
+  // Modify fields inside transaction and abort it.
+  Transaction transaction;
+  Runtime::Current()->EnterTransactionMode(&transaction);
+  booleanField->SetBoolean<true>(sirt_klass.get(), true);
+  byteField->SetByte<true>(sirt_klass.get(), 1);
+  charField->SetChar<true>(sirt_klass.get(), 1u);
+  shortField->SetShort<true>(sirt_klass.get(), 1);
+  intField->SetInt<true>(sirt_klass.get(), 1);
+  longField->SetLong<true>(sirt_klass.get(), 1);
+  floatField->SetFloat<true>(sirt_klass.get(), 1.0);
+  doubleField->SetDouble<true>(sirt_klass.get(), 1.0);
+  objectField->SetObject<true>(sirt_klass.get(), sirt_obj.get());
+  Runtime::Current()->ExitTransactionMode();
+  transaction.Abort();
+
+  // Check values have properly been restored to their original (default) value.
+  EXPECT_EQ(booleanField->GetBoolean(sirt_klass.get()), false);
+  EXPECT_EQ(byteField->GetByte(sirt_klass.get()), 0);
+  EXPECT_EQ(charField->GetChar(sirt_klass.get()), 0u);
+  EXPECT_EQ(shortField->GetShort(sirt_klass.get()), 0);
+  EXPECT_EQ(intField->GetInt(sirt_klass.get()), 0);
+  EXPECT_EQ(longField->GetLong(sirt_klass.get()), static_cast<int64_t>(0));
+  EXPECT_EQ(floatField->GetFloat(sirt_klass.get()), static_cast<float>(0.0f));
+  EXPECT_EQ(doubleField->GetDouble(sirt_klass.get()), static_cast<double>(0.0));
+  EXPECT_EQ(objectField->GetObject(sirt_klass.get()), nullptr);
+}
+
+TEST_F(TransactionTest, InstanceFieldsTest) {
+  ScopedObjectAccess soa(Thread::Current());
+  SirtRef<mirror::ClassLoader> class_loader(
+      soa.Self(), soa.Decode<mirror::ClassLoader*>(LoadDex("Transaction")));
+  ASSERT_TRUE(class_loader.get() != nullptr);
+
+  SirtRef<mirror::Class> sirt_klass(soa.Self(),
+                                    class_linker_->FindClass("LInstanceFieldsTest;", class_loader));
+  ASSERT_TRUE(sirt_klass.get() != nullptr);
+  class_linker_->EnsureInitialized(sirt_klass, true, true);
+  ASSERT_TRUE(sirt_klass->IsInitialized());
+
+  // Allocate an InstanceFieldTest object.
+  SirtRef<mirror::Object> sirt_instance(soa.Self(), sirt_klass->AllocObject(soa.Self()));
+  ASSERT_TRUE(sirt_instance.get() != nullptr);
+
+  // Lookup fields.
+  mirror::ArtField* booleanField = sirt_klass->FindDeclaredInstanceField("booleanField", "Z");
+  ASSERT_TRUE(booleanField != nullptr);
+  ASSERT_EQ(FieldHelper(booleanField).GetTypeAsPrimitiveType(), Primitive::kPrimBoolean);
+  ASSERT_EQ(booleanField->GetBoolean(sirt_instance.get()), false);
+
+  mirror::ArtField* byteField = sirt_klass->FindDeclaredInstanceField("byteField", "B");
+  ASSERT_TRUE(byteField != nullptr);
+  ASSERT_EQ(FieldHelper(byteField).GetTypeAsPrimitiveType(), Primitive::kPrimByte);
+  ASSERT_EQ(byteField->GetByte(sirt_instance.get()), 0);
+
+  mirror::ArtField* charField = sirt_klass->FindDeclaredInstanceField("charField", "C");
+  ASSERT_TRUE(charField != nullptr);
+  ASSERT_EQ(FieldHelper(charField).GetTypeAsPrimitiveType(), Primitive::kPrimChar);
+  ASSERT_EQ(charField->GetChar(sirt_instance.get()), 0u);
+
+  mirror::ArtField* shortField = sirt_klass->FindDeclaredInstanceField("shortField", "S");
+  ASSERT_TRUE(shortField != nullptr);
+  ASSERT_EQ(FieldHelper(shortField).GetTypeAsPrimitiveType(), Primitive::kPrimShort);
+  ASSERT_EQ(shortField->GetShort(sirt_instance.get()), 0);
+
+  mirror::ArtField* intField = sirt_klass->FindDeclaredInstanceField("intField", "I");
+  ASSERT_TRUE(intField != nullptr);
+  ASSERT_EQ(FieldHelper(intField).GetTypeAsPrimitiveType(), Primitive::kPrimInt);
+  ASSERT_EQ(intField->GetInt(sirt_instance.get()), 0);
+
+  mirror::ArtField* longField = sirt_klass->FindDeclaredInstanceField("longField", "J");
+  ASSERT_TRUE(longField != nullptr);
+  ASSERT_EQ(FieldHelper(longField).GetTypeAsPrimitiveType(), Primitive::kPrimLong);
+  ASSERT_EQ(longField->GetLong(sirt_instance.get()), static_cast<int64_t>(0));
+
+  mirror::ArtField* floatField = sirt_klass->FindDeclaredInstanceField("floatField", "F");
+  ASSERT_TRUE(floatField != nullptr);
+  ASSERT_EQ(FieldHelper(floatField).GetTypeAsPrimitiveType(), Primitive::kPrimFloat);
+  ASSERT_EQ(floatField->GetFloat(sirt_instance.get()), static_cast<float>(0.0f));
+
+  mirror::ArtField* doubleField = sirt_klass->FindDeclaredInstanceField("doubleField", "D");
+  ASSERT_TRUE(doubleField != nullptr);
+  ASSERT_EQ(FieldHelper(doubleField).GetTypeAsPrimitiveType(), Primitive::kPrimDouble);
+  ASSERT_EQ(doubleField->GetDouble(sirt_instance.get()), static_cast<double>(0.0));
+
+  mirror::ArtField* objectField = sirt_klass->FindDeclaredInstanceField("objectField", "Ljava/lang/Object;");
+  ASSERT_TRUE(objectField != nullptr);
+  ASSERT_EQ(FieldHelper(objectField).GetTypeAsPrimitiveType(), Primitive::kPrimNot);
+  ASSERT_EQ(objectField->GetObject(sirt_instance.get()), nullptr);
+
+  // Create a java.lang.Object instance to set objectField.
+  SirtRef<mirror::Class> object_klass(soa.Self(), class_linker_->FindSystemClass("Ljava/lang/Object;"));
+  ASSERT_TRUE(object_klass.get() != nullptr);
+  SirtRef<mirror::Object> sirt_obj(soa.Self(), sirt_klass->AllocObject(soa.Self()));
+  ASSERT_TRUE(sirt_obj.get() != nullptr);
+  ASSERT_EQ(sirt_obj->GetClass(), sirt_klass.get());
+
+  // Modify fields inside transaction and abort it.
+  Transaction transaction;
+  Runtime::Current()->EnterTransactionMode(&transaction);
+  booleanField->SetBoolean<true>(sirt_instance.get(), true);
+  byteField->SetByte<true>(sirt_instance.get(), 1);
+  charField->SetChar<true>(sirt_instance.get(), 1u);
+  shortField->SetShort<true>(sirt_instance.get(), 1);
+  intField->SetInt<true>(sirt_instance.get(), 1);
+  longField->SetLong<true>(sirt_instance.get(), 1);
+  floatField->SetFloat<true>(sirt_instance.get(), 1.0);
+  doubleField->SetDouble<true>(sirt_instance.get(), 1.0);
+  objectField->SetObject<true>(sirt_instance.get(), sirt_obj.get());
+  Runtime::Current()->ExitTransactionMode();
+  transaction.Abort();
+
+  // Check values have properly been restored to their original (default) value.
+  EXPECT_EQ(booleanField->GetBoolean(sirt_instance.get()), false);
+  EXPECT_EQ(byteField->GetByte(sirt_instance.get()), 0);
+  EXPECT_EQ(charField->GetChar(sirt_instance.get()), 0u);
+  EXPECT_EQ(shortField->GetShort(sirt_instance.get()), 0);
+  EXPECT_EQ(intField->GetInt(sirt_instance.get()), 0);
+  EXPECT_EQ(longField->GetLong(sirt_instance.get()), static_cast<int64_t>(0));
+  EXPECT_EQ(floatField->GetFloat(sirt_instance.get()), static_cast<float>(0.0f));
+  EXPECT_EQ(doubleField->GetDouble(sirt_instance.get()), static_cast<double>(0.0));
+  EXPECT_EQ(objectField->GetObject(sirt_instance.get()), nullptr);
+}
+
+
+TEST_F(TransactionTest, StaticArrayFieldsTest) {
+  ScopedObjectAccess soa(Thread::Current());
+  SirtRef<mirror::ClassLoader> class_loader(
+      soa.Self(), soa.Decode<mirror::ClassLoader*>(LoadDex("Transaction")));
+  ASSERT_TRUE(class_loader.get() != nullptr);
+
+  SirtRef<mirror::Class> sirt_klass(soa.Self(),
+                                    class_linker_->FindClass("LStaticArrayFieldsTest;", class_loader));
+  ASSERT_TRUE(sirt_klass.get() != nullptr);
+  class_linker_->EnsureInitialized(sirt_klass, true, true);
+  ASSERT_TRUE(sirt_klass->IsInitialized());
+
+  // Lookup fields.
+  mirror::ArtField* booleanArrayField = sirt_klass->FindDeclaredStaticField("booleanArrayField", "[Z");
+  ASSERT_TRUE(booleanArrayField != nullptr);
+  mirror::BooleanArray* booleanArray = booleanArrayField->GetObject(sirt_klass.get())->AsBooleanArray();
+  ASSERT_TRUE(booleanArray != nullptr);
+  ASSERT_EQ(booleanArray->GetLength(), 1);
+  ASSERT_EQ(booleanArray->GetWithoutChecks(0), false);
+
+  mirror::ArtField* byteArrayField = sirt_klass->FindDeclaredStaticField("byteArrayField", "[B");
+  ASSERT_TRUE(byteArrayField != nullptr);
+  mirror::ByteArray* byteArray = byteArrayField->GetObject(sirt_klass.get())->AsByteArray();
+  ASSERT_TRUE(byteArray != nullptr);
+  ASSERT_EQ(byteArray->GetLength(), 1);
+  ASSERT_EQ(byteArray->GetWithoutChecks(0), 0);
+
+  mirror::ArtField* charArrayField = sirt_klass->FindDeclaredStaticField("charArrayField", "[C");
+  ASSERT_TRUE(charArrayField != nullptr);
+  mirror::CharArray* charArray = charArrayField->GetObject(sirt_klass.get())->AsCharArray();
+  ASSERT_TRUE(charArray != nullptr);
+  ASSERT_EQ(charArray->GetLength(), 1);
+  ASSERT_EQ(charArray->GetWithoutChecks(0), 0u);
+
+  mirror::ArtField* shortArrayField = sirt_klass->FindDeclaredStaticField("shortArrayField", "[S");
+  ASSERT_TRUE(shortArrayField != nullptr);
+  mirror::ShortArray* shortArray = shortArrayField->GetObject(sirt_klass.get())->AsShortArray();
+  ASSERT_TRUE(shortArray != nullptr);
+  ASSERT_EQ(shortArray->GetLength(), 1);
+  ASSERT_EQ(shortArray->GetWithoutChecks(0), 0);
+
+  mirror::ArtField* intArrayField = sirt_klass->FindDeclaredStaticField("intArrayField", "[I");
+  ASSERT_TRUE(intArrayField != nullptr);
+  mirror::IntArray* intArray = intArrayField->GetObject(sirt_klass.get())->AsIntArray();
+  ASSERT_TRUE(intArray != nullptr);
+  ASSERT_EQ(intArray->GetLength(), 1);
+  ASSERT_EQ(intArray->GetWithoutChecks(0), 0);
+
+  mirror::ArtField* longArrayField = sirt_klass->FindDeclaredStaticField("longArrayField", "[J");
+  ASSERT_TRUE(longArrayField != nullptr);
+  mirror::LongArray* longArray = longArrayField->GetObject(sirt_klass.get())->AsLongArray();
+  ASSERT_TRUE(longArray != nullptr);
+  ASSERT_EQ(longArray->GetLength(), 1);
+  ASSERT_EQ(longArray->GetWithoutChecks(0), static_cast<int64_t>(0));
+
+  mirror::ArtField* floatArrayField = sirt_klass->FindDeclaredStaticField("floatArrayField", "[F");
+  ASSERT_TRUE(floatArrayField != nullptr);
+  mirror::FloatArray* floatArray = floatArrayField->GetObject(sirt_klass.get())->AsFloatArray();
+  ASSERT_TRUE(floatArray != nullptr);
+  ASSERT_EQ(floatArray->GetLength(), 1);
+  ASSERT_EQ(floatArray->GetWithoutChecks(0), static_cast<float>(0.0f));
+
+  mirror::ArtField* doubleArrayField = sirt_klass->FindDeclaredStaticField("doubleArrayField", "[D");
+  ASSERT_TRUE(doubleArrayField != nullptr);
+  mirror::DoubleArray* doubleArray = doubleArrayField->GetObject(sirt_klass.get())->AsDoubleArray();
+  ASSERT_TRUE(doubleArray != nullptr);
+  ASSERT_EQ(doubleArray->GetLength(), 1);
+  ASSERT_EQ(doubleArray->GetWithoutChecks(0), static_cast<double>(0.0f));
+
+  mirror::ArtField* objectArrayField = sirt_klass->FindDeclaredStaticField("objectArrayField", "[Ljava/lang/Object;");
+  ASSERT_TRUE(objectArrayField != nullptr);
+  mirror::ObjectArray<mirror::Object>* objectArray = objectArrayField->GetObject(sirt_klass.get())->AsObjectArray<mirror::Object>();
+  ASSERT_TRUE(objectArray != nullptr);
+  ASSERT_EQ(objectArray->GetLength(), 1);
+  ASSERT_EQ(objectArray->GetWithoutChecks(0), nullptr);
+
+  // Create a java.lang.Object instance to set objectField.
+  SirtRef<mirror::Class> object_klass(soa.Self(), class_linker_->FindSystemClass("Ljava/lang/Object;"));
+  ASSERT_TRUE(object_klass.get() != nullptr);
+  SirtRef<mirror::Object> sirt_obj(soa.Self(), sirt_klass->AllocObject(soa.Self()));
+  ASSERT_TRUE(sirt_obj.get() != nullptr);
+  ASSERT_EQ(sirt_obj->GetClass(), sirt_klass.get());
+
+  // Modify fields inside transaction and abort it.
+  Transaction transaction;
+  Runtime::Current()->EnterTransactionMode(&transaction);
+  booleanArray->SetWithoutChecks<true>(0, true);
+  byteArray->SetWithoutChecks<true>(0, 1);
+  charArray->SetWithoutChecks<true>(0, 1u);
+  shortArray->SetWithoutChecks<true>(0, 1);
+  intArray->SetWithoutChecks<true>(0, 1);
+  longArray->SetWithoutChecks<true>(0, 1);
+  floatArray->SetWithoutChecks<true>(0, 1.0);
+  doubleArray->SetWithoutChecks<true>(0, 1.0);
+  objectArray->SetWithoutChecks<true>(0, sirt_obj.get());
+  Runtime::Current()->ExitTransactionMode();
+  transaction.Abort();
+
+  // Check values have properly been restored to their original (default) value.
+  EXPECT_EQ(booleanArray->GetWithoutChecks(0), false);
+  EXPECT_EQ(byteArray->GetWithoutChecks(0), 0);
+  EXPECT_EQ(charArray->GetWithoutChecks(0), 0u);
+  EXPECT_EQ(shortArray->GetWithoutChecks(0), 0);
+  EXPECT_EQ(intArray->GetWithoutChecks(0), 0);
+  EXPECT_EQ(longArray->GetWithoutChecks(0), static_cast<int64_t>(0));
+  EXPECT_EQ(floatArray->GetWithoutChecks(0), static_cast<float>(0.0f));
+  EXPECT_EQ(doubleArray->GetWithoutChecks(0), static_cast<double>(0.0f));
+  EXPECT_EQ(objectArray->GetWithoutChecks(0), nullptr);
+}
+
+TEST_F(TransactionTest, EmptyClass) {
+  ScopedObjectAccess soa(Thread::Current());
+  SirtRef<mirror::ClassLoader> class_loader(
+      soa.Self(), soa.Decode<mirror::ClassLoader*>(LoadDex("Transaction")));
+  ASSERT_TRUE(class_loader.get() != nullptr);
+
+  SirtRef<mirror::Class> sirt_klass(soa.Self(),
+                                    class_linker_->FindClass("LTransaction$EmptyStatic;", class_loader));
+  ASSERT_TRUE(sirt_klass.get() != nullptr);
+  class_linker_->VerifyClass(sirt_klass);
+  ASSERT_TRUE(sirt_klass->IsVerified());
+
+  Transaction transaction;
+  Runtime::Current()->EnterTransactionMode(&transaction);
+  class_linker_->EnsureInitialized(sirt_klass, true, true);
+  Runtime::Current()->ExitTransactionMode();
+  ASSERT_FALSE(soa.Self()->IsExceptionPending());
+}
+
+TEST_F(TransactionTest, StaticFieldClass) {
+  ScopedObjectAccess soa(Thread::Current());
+  SirtRef<mirror::ClassLoader> class_loader(
+      soa.Self(), soa.Decode<mirror::ClassLoader*>(LoadDex("Transaction")));
+  ASSERT_TRUE(class_loader.get() != nullptr);
+
+  SirtRef<mirror::Class> sirt_klass(soa.Self(),
+                                    class_linker_->FindClass("LTransaction$StaticFieldClass;", class_loader));
+  ASSERT_TRUE(sirt_klass.get() != nullptr);
+  class_linker_->VerifyClass(sirt_klass);
+  ASSERT_TRUE(sirt_klass->IsVerified());
+
+  Transaction transaction;
+  Runtime::Current()->EnterTransactionMode(&transaction);
+  class_linker_->EnsureInitialized(sirt_klass, true, true);
+  Runtime::Current()->ExitTransactionMode();
+  ASSERT_FALSE(soa.Self()->IsExceptionPending());
+}
+
+TEST_F(TransactionTest, BlacklistedClass) {
+  ScopedObjectAccess soa(Thread::Current());
+  jobject jclass_loader = LoadDex("Transaction");
+  SirtRef<mirror::ClassLoader> class_loader(soa.Self(),
+                                            soa.Decode<mirror::ClassLoader*>(jclass_loader));
+  ASSERT_TRUE(class_loader.get() != nullptr);
+
+  // Load and verify java.lang.ExceptionInInitializerError and java.lang.InternalError which will
+  // be thrown by class initialization due to native call.
+  SirtRef<mirror::Class> sirt_klass(soa.Self(),
+                                    class_linker_->FindSystemClass("Ljava/lang/ExceptionInInitializerError;"));
+  ASSERT_TRUE(sirt_klass.get() != nullptr);
+  class_linker_->VerifyClass(sirt_klass);
+  ASSERT_TRUE(sirt_klass->IsVerified());
+  sirt_klass.reset(class_linker_->FindSystemClass("Ljava/lang/InternalError;"));
+  ASSERT_TRUE(sirt_klass.get() != nullptr);
+  class_linker_->VerifyClass(sirt_klass);
+  ASSERT_TRUE(sirt_klass->IsVerified());
+
+  // Load and verify Transaction$NativeSupport used in class initialization.
+  sirt_klass.reset(class_linker_->FindClass("LTransaction$NativeSupport;", class_loader));
+  ASSERT_TRUE(sirt_klass.get() != nullptr);
+  class_linker_->VerifyClass(sirt_klass);
+  ASSERT_TRUE(sirt_klass->IsVerified());
+
+  sirt_klass.reset(class_linker_->FindClass("LTransaction$BlacklistedClass;", class_loader));
+  ASSERT_TRUE(sirt_klass.get() != nullptr);
+  class_linker_->VerifyClass(sirt_klass);
+  ASSERT_TRUE(sirt_klass->IsVerified());
+
+  Transaction transaction;
+  Runtime::Current()->EnterTransactionMode(&transaction);
+  class_linker_->EnsureInitialized(sirt_klass, true, true);
+  Runtime::Current()->ExitTransactionMode();
+  ASSERT_TRUE(soa.Self()->IsExceptionPending());
+}
+
+
+}  // namespace art
diff --git a/test/Android.mk b/test/Android.mk
index 4d47651..dcf75d0 100644
--- a/test/Android.mk
+++ b/test/Android.mk
@@ -36,6 +36,7 @@
 	StaticLeafMethods \
 	Statics \
 	StaticsFromCode \
+	Transaction \
 	XandY
 
 # subdirectories of which are used with test-art-target-oat
diff --git a/test/Transaction/InstanceFieldsTest.java b/test/Transaction/InstanceFieldsTest.java
new file mode 100644
index 0000000..38a44d2
--- /dev/null
+++ b/test/Transaction/InstanceFieldsTest.java
@@ -0,0 +1,27 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+public class InstanceFieldsTest {
+    public boolean booleanField;
+    public byte    byteField;
+    public char    charField;
+    public short   shortField;
+    public int     intField;
+    public long    longField;
+    public float   floatField;
+    public double  doubleField;
+    public Object  objectField;
+}
diff --git a/test/Transaction/StaticArrayFieldsTest.java b/test/Transaction/StaticArrayFieldsTest.java
new file mode 100644
index 0000000..6436839
--- /dev/null
+++ b/test/Transaction/StaticArrayFieldsTest.java
@@ -0,0 +1,27 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+public class StaticArrayFieldsTest {
+    public static boolean[] booleanArrayField = new boolean[1];
+    public static byte[]    byteArrayField = new byte[1];
+    public static char []   charArrayField = new char[1];
+    public static short[]   shortArrayField = new short[1];
+    public static int[]     intArrayField = new int[1];
+    public static long[]    longArrayField = new long[1];
+    public static float[]   floatArrayField = new float[1];
+    public static double[]  doubleArrayField = new double[1];
+    public static Object[]  objectArrayField = new Object[1];
+}
diff --git a/test/Transaction/StaticFieldsTest.java b/test/Transaction/StaticFieldsTest.java
new file mode 100644
index 0000000..2316f3b
--- /dev/null
+++ b/test/Transaction/StaticFieldsTest.java
@@ -0,0 +1,27 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+public class StaticFieldsTest {
+    public static boolean booleanField;
+    public static byte    byteField;
+    public static char    charField;
+    public static short   shortField;
+    public static int     intField;
+    public static long    longField;
+    public static float   floatField;
+    public static double  doubleField;
+    public static Object  objectField;
+}
diff --git a/test/Transaction/Transaction.java b/test/Transaction/Transaction.java
new file mode 100644
index 0000000..9ca7fbf
--- /dev/null
+++ b/test/Transaction/Transaction.java
@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+public class Transaction {
+    static class EmptyStatic {
+    }
+
+    static class StaticFieldClass {
+      public static int intField;
+      static {
+        intField = 5;
+      }
+    }
+
+    static class BlacklistedClass {
+      static {
+        NativeSupport.native_call();
+      }
+    }
+
+    static class NativeSupport {
+      public static native void native_call();
+    }
+}