diff --git a/runtime/dex_method_iterator.h b/runtime/dex_method_iterator.h
index cb71cb5..e915d77 100644
--- a/runtime/dex_method_iterator.h
+++ b/runtime/dex_method_iterator.h
@@ -25,7 +25,7 @@
 
 class DexMethodIterator {
  public:
-  DexMethodIterator(const std::vector<const DexFile*>& dex_files)
+  explicit DexMethodIterator(const std::vector<const DexFile*>& dex_files)
       : dex_files_(dex_files),
         found_next_(false),
         dex_file_index_(0),