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/*
* Copyright (C) 2012 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.
*/
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Map;
import java.util.Random;
public class ConcurrentGC {
private static final int buckets = 16 * 1024;
private static final int bufferSize = 1024;
static class ByteContainer {
public byte[] bytes;
}
public static void main(String[] args) throws Exception {
try {
ByteContainer[] l = new ByteContainer[buckets];
for (int i = 0; i < buckets; ++i) {
l[i] = new ByteContainer();
}
Random rnd = new Random(123456);
for (int i = 0; i < buckets / 256; ++i) {
int index = rnd.nextInt(buckets);
l[index].bytes = new byte[bufferSize];
// Try to get GC to run if we can
Runtime.getRuntime().gc();
// Shuffle the array to try cause the lost object problem:
// This problem occurs when an object is white, it may be
// only referenced from a white or grey object. If the white
// object is moved during a CMS to be a black object's field, it
// causes the moved object to not get marked. This can result in
// heap corruption. A typical way to address this issue is by
// having a card table.
// This aspect of the test is meant to ensure that card
// dirtying works and that we check the marked cards after
// marking.
// If these operations are not done, a segfault / failed assert
// should occur.
for (int j = 0; j < l.length; ++j) {
int a = l.length - i - 1;
int b = rnd.nextInt(a);
byte[] temp = l[a].bytes;
l[a].bytes = l[b].bytes;
l[b].bytes = temp;
}
}
} catch (OutOfMemoryError e) {
}
}
}
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