diff --git a/compiler/dex/arena_allocator.h b/compiler/dex/arena_allocator.h
index cc81e50..0ad859e 100644
--- a/compiler/dex/arena_allocator.h
+++ b/compiler/dex/arena_allocator.h
@@ -47,7 +47,7 @@
       kNumAllocKinds
     };
 
-  ArenaAllocator(size_t default_size = ARENA_DEFAULT_BLOCK_SIZE);
+  explicit ArenaAllocator(size_t default_size = ARENA_DEFAULT_BLOCK_SIZE);
   ~ArenaAllocator();
   void* NewMem(size_t size, bool zero, ArenaAllocKind kind);
   size_t BytesAllocated() {
@@ -86,7 +86,7 @@
      void Dump(std::ostream& os) const {
        arena_.DumpMemStats(os);
      }
-     MemStats(const ArenaAllocator &arena) : arena_(arena) {};
+     explicit MemStats(const ArenaAllocator &arena) : arena_(arena) {};
   private:
     const ArenaAllocator &arena_;
 }; // MemStats
diff --git a/compiler/dex/arena_bit_vector.h b/compiler/dex/arena_bit_vector.h
index 0b7bbc5..7e5c436 100644
--- a/compiler/dex/arena_bit_vector.h
+++ b/compiler/dex/arena_bit_vector.h
@@ -33,7 +33,7 @@
 
     class Iterator {
       public:
-        Iterator(ArenaBitVector* bit_vector)
+        explicit Iterator(ArenaBitVector* bit_vector)
           : p_bits_(bit_vector),
             bit_storage_(bit_vector->GetRawStorage()),
             bit_index_(0),
diff --git a/compiler/dex/backend.h b/compiler/dex/backend.h
index 6f5ba38..7fa8e99 100644
--- a/compiler/dex/backend.h
+++ b/compiler/dex/backend.h
@@ -30,7 +30,7 @@
     virtual CompiledMethod* GetCompiledMethod() = 0;
 
   protected:
-    Backend(ArenaAllocator* arena) : arena_(arena) {};
+    explicit Backend(ArenaAllocator* arena) : arena_(arena) {};
     ArenaAllocator* const arena_;
 
 };  // Class Backend
diff --git a/compiler/dex/growable_array.h b/compiler/dex/growable_array.h
index 6ab0f16..6d26bc2 100644
--- a/compiler/dex/growable_array.h
+++ b/compiler/dex/growable_array.h
@@ -49,7 +49,7 @@
 
     class Iterator {
       public:
-        Iterator(GrowableArray* g_list)
+        explicit Iterator(GrowableArray* g_list)
           : idx_(0),
             g_list_(g_list) {};
 
diff --git a/compiler/dex/local_value_numbering.h b/compiler/dex/local_value_numbering.h
index f2b2291..09ed7ae 100644
--- a/compiler/dex/local_value_numbering.h
+++ b/compiler/dex/local_value_numbering.h
@@ -33,7 +33,7 @@
 
 class LocalValueNumbering {
  public:
-  LocalValueNumbering(CompilationUnit* cu) : cu_(cu) {};
+  explicit LocalValueNumbering(CompilationUnit* cu) : cu_(cu) {};
 
   static uint64_t BuildKey(uint16_t op, uint16_t operand1, uint16_t operand2, uint16_t modifier) {
     return (static_cast<uint64_t>(op) << 48 | static_cast<uint64_t>(operand1) << 32 |
diff --git a/compiler/driver/dex_compilation_unit.h b/compiler/driver/dex_compilation_unit.h
index 53efd12..facc9cb 100644
--- a/compiler/driver/dex_compilation_unit.h
+++ b/compiler/driver/dex_compilation_unit.h
@@ -32,7 +32,7 @@
 
 class DexCompilationUnit {
  public:
-  DexCompilationUnit(CompilationUnit* cu);
+  explicit DexCompilationUnit(CompilationUnit* cu);
 
   DexCompilationUnit(CompilationUnit* cu, jobject class_loader, ClassLinker* class_linker,
                      const DexFile& dex_file, const DexFile::CodeItem* code_item,
diff --git a/compiler/llvm/md_builder.h b/compiler/llvm/md_builder.h
index cc169a3..65c52c9 100644
--- a/compiler/llvm/md_builder.h
+++ b/compiler/llvm/md_builder.h
@@ -35,7 +35,7 @@
 
 class MDBuilder : public LLVMMDBuilder {
  public:
-  MDBuilder(::llvm::LLVMContext& context)
+  explicit MDBuilder(::llvm::LLVMContext& context)
      : LLVMMDBuilder(context), tbaa_root_(createTBAARoot("Art TBAA Root")) {
     std::memset(tbaa_special_type_, 0, sizeof(tbaa_special_type_));
     std::memset(tbaa_memory_jtype_, 0, sizeof(tbaa_memory_jtype_));
diff --git a/dex2oat/dex2oat.cc b/dex2oat/dex2oat.cc
index c73c1bb..541c916 100644
--- a/dex2oat/dex2oat.cc
+++ b/dex2oat/dex2oat.cc
@@ -456,7 +456,7 @@
   } while (false)
 
  public:
-  WatchDog(bool is_watch_dog_enabled) {
+  explicit WatchDog(bool is_watch_dog_enabled) {
     is_watch_dog_enabled_ = is_watch_dog_enabled;
     if (!is_watch_dog_enabled_) {
       return;
diff --git a/runtime/atomic_integer.h b/runtime/atomic_integer.h
index 57836d6..117e837 100644
--- a/runtime/atomic_integer.h
+++ b/runtime/atomic_integer.h
@@ -26,7 +26,7 @@
  public:
   AtomicInteger() : value_(0) { }
 
-  AtomicInteger(int32_t value) : value_(value) { }
+  explicit AtomicInteger(int32_t value) : value_(value) { }
 
   // Unsafe = operator for non atomic operations on the integer.
   AtomicInteger& operator = (int32_t new_value) {
diff --git a/runtime/barrier.h b/runtime/barrier.h
index e0ad239..22f08e1 100644
--- a/runtime/barrier.h
+++ b/runtime/barrier.h
@@ -25,7 +25,7 @@
 
 class Barrier {
  public:
-  Barrier(int count);
+  explicit Barrier(int count);
   virtual ~Barrier();
 
   // Pass through the barrier, decrements the count but does not block.
diff --git a/runtime/barrier_test.cc b/runtime/barrier_test.cc
index 55d2d3d..d26ae9e 100644
--- a/runtime/barrier_test.cc
+++ b/runtime/barrier_test.cc
@@ -69,9 +69,9 @@
   Thread* self = Thread::Current();
   ThreadPool thread_pool(num_threads);
   Barrier barrier(0);
-  AtomicInteger count1 = 0;
-  AtomicInteger count2 = 0;
-  AtomicInteger count3 = 0;
+  AtomicInteger count1(0);
+  AtomicInteger count2(0);
+  AtomicInteger count3(0);
   for (int32_t i = 0; i < num_threads; ++i) {
     thread_pool.AddTask(self, new CheckWaitTask(&barrier, &count1, &count2, &count3));
   }
@@ -126,7 +126,7 @@
   Thread* self = Thread::Current();
   ThreadPool thread_pool(num_threads);
   Barrier barrier(0);
-  AtomicInteger count = 0;
+  AtomicInteger count(0);
   const int32_t num_tasks = num_threads * 4;
   const int32_t num_sub_tasks = 128;
   for (int32_t i = 0; i < num_tasks; ++i) {
diff --git a/runtime/base/histogram.h b/runtime/base/histogram.h
index 8724d2c..dfb556b 100644
--- a/runtime/base/histogram.h
+++ b/runtime/base/histogram.h
@@ -36,7 +36,7 @@
   const size_t kInitialBucketCount;
 
  public:
-  Histogram(std::string);
+  explicit Histogram(std::string);
   void AddValue(Value);
   void CreateHistogram();
   void Reset();
diff --git a/runtime/base/mutex.cc b/runtime/base/mutex.cc
index bb4b5c5..25c0b9e 100644
--- a/runtime/base/mutex.cc
+++ b/runtime/base/mutex.cc
@@ -94,7 +94,7 @@
 
 class ScopedAllMutexesLock {
  public:
-  ScopedAllMutexesLock(const BaseMutex* mutex) : mutex_(mutex) {
+  explicit ScopedAllMutexesLock(const BaseMutex* mutex) : mutex_(mutex) {
     while (!all_mutexes_guard_.CompareAndSwap(0, reinterpret_cast<int32_t>(mutex))) {
       NanoSleep(100);
     }
diff --git a/runtime/debugger.cc b/runtime/debugger.cc
index fe726aa..5a31c87 100644
--- a/runtime/debugger.cc
+++ b/runtime/debugger.cc
@@ -1814,7 +1814,7 @@
 static int GetStackDepth(Thread* thread)
     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
   struct CountStackDepthVisitor : public StackVisitor {
-    CountStackDepthVisitor(Thread* thread)
+    explicit CountStackDepthVisitor(Thread* thread)
         : StackVisitor(thread, NULL), depth(0) {}
 
     // TODO: Enable annotalysis. We know lock is held in constructor, but abstraction confuses
@@ -2458,7 +2458,7 @@
   //
 
   struct SingleStepStackVisitor : public StackVisitor {
-    SingleStepStackVisitor(Thread* thread)
+    explicit SingleStepStackVisitor(Thread* thread)
         EXCLUSIVE_LOCKS_REQUIRED(Locks::breakpoint_lock_)
         SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
         : StackVisitor(thread, NULL) {
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),
diff --git a/runtime/file_output_stream.h b/runtime/file_output_stream.h
index 10405ef..23a57f5 100644
--- a/runtime/file_output_stream.h
+++ b/runtime/file_output_stream.h
@@ -25,7 +25,7 @@
 
 class FileOutputStream : public OutputStream {
  public:
-  FileOutputStream(File* file);
+  explicit FileOutputStream(File* file);
 
   virtual ~FileOutputStream() {}
 
diff --git a/runtime/gc/accounting/heap_bitmap.h b/runtime/gc/accounting/heap_bitmap.h
index a12809e..f4b725c 100644
--- a/runtime/gc/accounting/heap_bitmap.h
+++ b/runtime/gc/accounting/heap_bitmap.h
@@ -103,8 +103,7 @@
   void ReplaceObjectSet(SpaceSetMap* old_set, SpaceSetMap* new_set)
       EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_);
 
-  HeapBitmap(Heap* heap) : heap_(heap) {
-  }
+  explicit HeapBitmap(Heap* heap) : heap_(heap) {}
 
  private:
 
diff --git a/runtime/gc/accounting/mod_union_table-inl.h b/runtime/gc/accounting/mod_union_table-inl.h
index 32ac95f..9ea74d4 100644
--- a/runtime/gc/accounting/mod_union_table-inl.h
+++ b/runtime/gc/accounting/mod_union_table-inl.h
@@ -28,8 +28,7 @@
 // A mod-union table to record image references to the Zygote and alloc space.
 class ModUnionTableToZygoteAllocspace : public ModUnionTableReferenceCache {
 public:
-  ModUnionTableToZygoteAllocspace(Heap* heap) : ModUnionTableReferenceCache(heap) {
-  }
+  explicit ModUnionTableToZygoteAllocspace(Heap* heap) : ModUnionTableReferenceCache(heap) {}
 
   bool AddReference(const mirror::Object* /* obj */, const mirror::Object* ref) {
     const std::vector<space::ContinuousSpace*>& spaces = GetHeap()->GetContinuousSpaces();
@@ -48,8 +47,7 @@
 // A mod-union table to record Zygote references to the alloc space.
 class ModUnionTableToAllocspace : public ModUnionTableReferenceCache {
  public:
-  ModUnionTableToAllocspace(Heap* heap) : ModUnionTableReferenceCache(heap) {
-  }
+  explicit ModUnionTableToAllocspace(Heap* heap) : ModUnionTableReferenceCache(heap) {}
 
   bool AddReference(const mirror::Object* /* obj */, const mirror::Object* ref) {
     const std::vector<space::ContinuousSpace*>& spaces = GetHeap()->GetContinuousSpaces();
diff --git a/runtime/gc/accounting/mod_union_table.cc b/runtime/gc/accounting/mod_union_table.cc
index 05b68c4..aa02f82 100644
--- a/runtime/gc/accounting/mod_union_table.cc
+++ b/runtime/gc/accounting/mod_union_table.cc
@@ -117,8 +117,8 @@
 
 class ModUnionScanImageRootVisitor {
  public:
-  ModUnionScanImageRootVisitor(collector::MarkSweep* const mark_sweep) : mark_sweep_(mark_sweep) {
-  }
+  explicit ModUnionScanImageRootVisitor(collector::MarkSweep* const mark_sweep)
+      : mark_sweep_(mark_sweep) {}
 
   void operator ()(const Object* root) const
       EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_)
diff --git a/runtime/gc/accounting/mod_union_table.h b/runtime/gc/accounting/mod_union_table.h
index 5435625..d46281c 100644
--- a/runtime/gc/accounting/mod_union_table.h
+++ b/runtime/gc/accounting/mod_union_table.h
@@ -49,11 +49,9 @@
 // cleared between GC phases, reducing the number of dirty cards that need to be scanned.
 class ModUnionTable {
  public:
-  ModUnionTable(Heap* heap) : heap_(heap) {
-  }
+  explicit ModUnionTable(Heap* heap) : heap_(heap) {}
 
-  virtual ~ModUnionTable() {
-  }
+  virtual ~ModUnionTable() {}
 
   // Clear cards which map to a memory range of a space. This doesn't immediately update the
   // mod-union table, as updating the mod-union table may have an associated cost, such as
@@ -86,7 +84,7 @@
 // Reference caching implementation. Caches references pointing to alloc space(s) for each card.
 class ModUnionTableReferenceCache : public ModUnionTable {
  public:
-  ModUnionTableReferenceCache(Heap* heap) : ModUnionTable(heap) {}
+  explicit ModUnionTableReferenceCache(Heap* heap) : ModUnionTable(heap) {}
   virtual ~ModUnionTableReferenceCache() {}
 
   // Clear and store cards for a space.
@@ -122,7 +120,7 @@
 // Card caching implementation. Keeps track of which cards we cleared and only this information.
 class ModUnionTableCardCache : public ModUnionTable {
  public:
-  ModUnionTableCardCache(Heap* heap) : ModUnionTable(heap) {}
+  explicit ModUnionTableCardCache(Heap* heap) : ModUnionTable(heap) {}
   virtual ~ModUnionTableCardCache() {}
 
   // Clear and store cards for a space.
diff --git a/runtime/gc/accounting/space_bitmap.h b/runtime/gc/accounting/space_bitmap.h
index 32ab440..5a1bfe3 100644
--- a/runtime/gc/accounting/space_bitmap.h
+++ b/runtime/gc/accounting/space_bitmap.h
@@ -244,7 +244,7 @@
     }
   }
 
-  SpaceSetMap(const std::string& name) : name_(name) {}
+  explicit SpaceSetMap(const std::string& name) : name_(name) {}
   ~SpaceSetMap() {}
 
   Objects& GetObjects() {
diff --git a/runtime/gc/collector/mark_sweep.cc b/runtime/gc/collector/mark_sweep.cc
index 279796f..a5bad2f 100644
--- a/runtime/gc/collector/mark_sweep.cc
+++ b/runtime/gc/collector/mark_sweep.cc
@@ -70,8 +70,7 @@
 
 class SetFingerVisitor {
  public:
-  SetFingerVisitor(MarkSweep* const mark_sweep) : mark_sweep_(mark_sweep) {
-  }
+  explicit SetFingerVisitor(MarkSweep* const mark_sweep) : mark_sweep_(mark_sweep) {}
 
   void operator ()(void* finger) const {
     mark_sweep_->SetFinger(reinterpret_cast<Object*>(finger));
@@ -523,10 +522,7 @@
 
 class CheckObjectVisitor {
  public:
-  CheckObjectVisitor(MarkSweep* const mark_sweep)
-      : mark_sweep_(mark_sweep) {
-
-  }
+  explicit CheckObjectVisitor(MarkSweep* const mark_sweep) : mark_sweep_(mark_sweep) {}
 
   void operator ()(const Object* obj, const Object* ref, MemberOffset offset, bool is_static) const
       NO_THREAD_SAFETY_ANALYSIS {
@@ -566,8 +562,7 @@
 
 class ScanObjectVisitor {
  public:
-  ScanObjectVisitor(MarkSweep* const mark_sweep) : mark_sweep_(mark_sweep) {
-  }
+  explicit ScanObjectVisitor(MarkSweep* const mark_sweep) : mark_sweep_(mark_sweep) {}
 
   // TODO: Fixme when anotatalysis works with visitors.
   void operator ()(const Object* obj) const NO_THREAD_SAFETY_ANALYSIS {
@@ -612,8 +607,7 @@
 
 class CheckBitmapVisitor {
  public:
-  CheckBitmapVisitor(MarkSweep* mark_sweep) : mark_sweep_(mark_sweep) {
-  }
+  explicit CheckBitmapVisitor(MarkSweep* mark_sweep) : mark_sweep_(mark_sweep) {}
 
   void operator ()(const Object* obj) const NO_THREAD_SAFETY_ANALYSIS {
     if (kDebugLocking) {
@@ -805,9 +799,7 @@
 
 class CheckpointMarkThreadRoots : public Closure {
  public:
-  CheckpointMarkThreadRoots(MarkSweep* mark_sweep) : mark_sweep_(mark_sweep) {
-
-  }
+  explicit CheckpointMarkThreadRoots(MarkSweep* mark_sweep) : mark_sweep_(mark_sweep) {}
 
   virtual void Run(Thread* thread) NO_THREAD_SAFETY_ANALYSIS {
     // Note: self is not necessarily equal to thread since thread may be suspended.
@@ -1086,8 +1078,7 @@
 
 class MarkObjectVisitor {
  public:
-  MarkObjectVisitor(MarkSweep* const mark_sweep) : mark_sweep_(mark_sweep) {
-  }
+  explicit MarkObjectVisitor(MarkSweep* const mark_sweep) : mark_sweep_(mark_sweep) {}
 
   // TODO: Fixme when anotatalysis works with visitors.
   void operator ()(const Object* /* obj */, const Object* ref, const MemberOffset& /* offset */,
@@ -1155,9 +1146,7 @@
 
   class MarkObjectParallelVisitor {
    public:
-    MarkObjectParallelVisitor(MarkStackChunk* chunk_task) : chunk_task_(chunk_task) {
-
-    }
+    explicit MarkObjectParallelVisitor(MarkStackChunk* chunk_task) : chunk_task_(chunk_task) {}
 
     void operator ()(const Object* /* obj */, const Object* ref,
                      const MemberOffset& /* offset */, bool /* is_static */) const {
diff --git a/runtime/gc/heap.cc b/runtime/gc/heap.cc
index 53b8cd9..85b7bf0 100644
--- a/runtime/gc/heap.cc
+++ b/runtime/gc/heap.cc
@@ -1173,10 +1173,9 @@
 // Verify a reference from an object.
 class VerifyReferenceVisitor {
  public:
-  VerifyReferenceVisitor(Heap* heap)
+  explicit VerifyReferenceVisitor(Heap* heap)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_)
-      : heap_(heap), failed_(false) {
-  }
+      : heap_(heap), failed_(false) {}
 
   bool Failed() const {
     return failed_;
@@ -1263,8 +1262,7 @@
 // Verify all references within an object, for use with HeapBitmap::Visit.
 class VerifyObjectVisitor {
  public:
-  VerifyObjectVisitor(Heap* heap) : heap_(heap), failed_(false) {
-  }
+  explicit VerifyObjectVisitor(Heap* heap) : heap_(heap), failed_(false) {}
 
   void operator ()(const mirror::Object* obj) const
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) {
@@ -1376,11 +1374,9 @@
 
 class VerifyLiveStackReferences {
  public:
-  VerifyLiveStackReferences(Heap* heap)
+  explicit VerifyLiveStackReferences(Heap* heap)
       : heap_(heap),
-        failed_(false) {
-
-  }
+        failed_(false) {}
 
   void operator ()(const mirror::Object* obj) const
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) {
diff --git a/runtime/gc/space/large_object_space.h b/runtime/gc/space/large_object_space.h
index 74d9cca..db845db 100644
--- a/runtime/gc/space/large_object_space.h
+++ b/runtime/gc/space/large_object_space.h
@@ -61,7 +61,7 @@
 
  protected:
 
-  LargeObjectSpace(const std::string& name);
+  explicit LargeObjectSpace(const std::string& name);
 
   // Approximate number of bytes which have been allocated into the space.
   size_t num_bytes_allocated_;
@@ -91,7 +91,7 @@
   bool Contains(const mirror::Object* obj) const NO_THREAD_SAFETY_ANALYSIS;
 
 private:
-  LargeObjectMapSpace(const std::string& name);
+  explicit LargeObjectMapSpace(const std::string& name);
   virtual ~LargeObjectMapSpace() {}
 
   // Used to ensure mutual exclusion when the allocation spaces data structures are being modified.
diff --git a/runtime/gc_map.h b/runtime/gc_map.h
index 33d09f2..ffe54c4 100644
--- a/runtime/gc_map.h
+++ b/runtime/gc_map.h
@@ -27,7 +27,7 @@
 // Lightweight wrapper for native PC offset to reference bit maps.
 class NativePcOffsetToReferenceMap {
  public:
-  NativePcOffsetToReferenceMap(const uint8_t* data) : data_(data) {
+  explicit NativePcOffsetToReferenceMap(const uint8_t* data) : data_(data) {
     CHECK(data_ != NULL);
   }
 
diff --git a/runtime/jdwp/jdwp_adb.cc b/runtime/jdwp/jdwp_adb.cc
index 9652f60..9b9fe4c 100644
--- a/runtime/jdwp/jdwp_adb.cc
+++ b/runtime/jdwp/jdwp_adb.cc
@@ -54,7 +54,7 @@
 
 struct JdwpAdbState : public JdwpNetStateBase {
  public:
-  JdwpAdbState(JdwpState* state) : JdwpNetStateBase(state) {
+  explicit JdwpAdbState(JdwpState* state) : JdwpNetStateBase(state) {
     control_sock_ = -1;
     shutting_down_ = false;
 
diff --git a/runtime/jdwp/jdwp_priv.h b/runtime/jdwp/jdwp_priv.h
index ab89339..557632c 100644
--- a/runtime/jdwp/jdwp_priv.h
+++ b/runtime/jdwp/jdwp_priv.h
@@ -53,7 +53,7 @@
  */
 class JdwpNetStateBase {
  public:
-  JdwpNetStateBase(JdwpState*);
+  explicit JdwpNetStateBase(JdwpState*);
   virtual ~JdwpNetStateBase();
 
   virtual bool Accept() = 0;
diff --git a/runtime/jdwp/jdwp_socket.cc b/runtime/jdwp/jdwp_socket.cc
index 08b4859..87706a4 100644
--- a/runtime/jdwp/jdwp_socket.cc
+++ b/runtime/jdwp/jdwp_socket.cc
@@ -46,7 +46,7 @@
   uint16_t listenPort;
   int     listenSock;         /* listen for connection from debugger */
 
-  JdwpSocketState(JdwpState* state) : JdwpNetStateBase(state) {
+  explicit JdwpSocketState(JdwpState* state) : JdwpNetStateBase(state) {
     listenPort  = 0;
     listenSock  = -1;
   }
diff --git a/runtime/monitor.h b/runtime/monitor.h
index 9206131..3b06217 100644
--- a/runtime/monitor.h
+++ b/runtime/monitor.h
@@ -196,7 +196,7 @@
 // For use only by the JDWP implementation.
 class MonitorInfo {
  public:
-  MonitorInfo(mirror::Object* o) EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_);
+  explicit MonitorInfo(mirror::Object* o) EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_);
 
   Thread* owner;
   size_t entry_count;
diff --git a/runtime/oat/utils/x86/assembler_x86.h b/runtime/oat/utils/x86/assembler_x86.h
index 390f7aa..3f40a54 100644
--- a/runtime/oat/utils/x86/assembler_x86.h
+++ b/runtime/oat/utils/x86/assembler_x86.h
@@ -643,7 +643,7 @@
 // Slowpath entered when Thread::Current()->_exception is non-null
 class X86ExceptionSlowPath : public SlowPath {
  public:
-  X86ExceptionSlowPath(size_t stack_adjust) : stack_adjust_(stack_adjust) {}
+  explicit X86ExceptionSlowPath(size_t stack_adjust) : stack_adjust_(stack_adjust) {}
   virtual void Emit(Assembler *sp_asm);
  private:
   const size_t stack_adjust_;
diff --git a/runtime/output_stream.h b/runtime/output_stream.h
index d2a77d8..aff6bcd 100644
--- a/runtime/output_stream.h
+++ b/runtime/output_stream.h
@@ -33,7 +33,7 @@
 
 class OutputStream {
  public:
-  OutputStream(const std::string& location) : location_(location) {}
+  explicit OutputStream(const std::string& location) : location_(location) {}
 
   virtual ~OutputStream() {}
 
diff --git a/runtime/thread.cc b/runtime/thread.cc
index 269d58e..6114c63 100644
--- a/runtime/thread.cc
+++ b/runtime/thread.cc
@@ -1256,7 +1256,7 @@
 
 class CountStackDepthVisitor : public StackVisitor {
  public:
-  CountStackDepthVisitor(Thread* thread)
+  explicit CountStackDepthVisitor(Thread* thread)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
       : StackVisitor(thread, NULL),
         depth_(0), skip_depth_(0), skipping_(true) {}
diff --git a/runtime/thread_pool.h b/runtime/thread_pool.h
index 3462d5e..b9f185d 100644
--- a/runtime/thread_pool.h
+++ b/runtime/thread_pool.h
@@ -76,7 +76,7 @@
   // after running it, it is the caller's responsibility.
   void AddTask(Thread* self, Task* task);
 
-  ThreadPool(size_t num_threads);
+  explicit ThreadPool(size_t num_threads);
   virtual ~ThreadPool();
 
   // Wait for all tasks currently on queue to get completed.
@@ -161,7 +161,7 @@
 
 class WorkStealingThreadPool : public ThreadPool {
  public:
-  WorkStealingThreadPool(size_t num_threads);
+  explicit WorkStealingThreadPool(size_t num_threads);
   virtual ~WorkStealingThreadPool();
 
  private:
diff --git a/runtime/thread_pool_test.cc b/runtime/thread_pool_test.cc
index e2a32f5..9b66318 100644
--- a/runtime/thread_pool_test.cc
+++ b/runtime/thread_pool_test.cc
@@ -25,8 +25,7 @@
 
 class CountTask : public Task {
  public:
-  CountTask(AtomicInteger* count) : count_(count), verbose_(false) {
-  }
+  explicit CountTask(AtomicInteger* count) : count_(count), verbose_(false) {}
 
   void Run(Thread* self) {
     if (verbose_) {
@@ -61,7 +60,7 @@
 TEST_F(ThreadPoolTest, CheckRun) {
   Thread* self = Thread::Current();
   ThreadPool thread_pool(num_threads);
-  AtomicInteger count = 0;
+  AtomicInteger count(0);
   static const int32_t num_tasks = num_threads * 4;
   for (int32_t i = 0; i < num_tasks; ++i) {
     thread_pool.AddTask(self, new CountTask(&count));
@@ -76,7 +75,7 @@
 TEST_F(ThreadPoolTest, StopStart) {
   Thread* self = Thread::Current();
   ThreadPool thread_pool(num_threads);
-  AtomicInteger count = 0;
+  AtomicInteger count(0);
   static const int32_t num_tasks = num_threads * 4;
   for (int32_t i = 0; i < num_tasks; ++i) {
     thread_pool.AddTask(self, new CountTask(&count));
@@ -88,7 +87,7 @@
   thread_pool.StartWorkers(self);
   usleep(200);
   thread_pool.StopWorkers(self);
-  AtomicInteger bad_count = 0;
+  AtomicInteger bad_count(0);
   thread_pool.AddTask(self, new CountTask(&bad_count));
   usleep(200);
   // Ensure that the task added after the workers were stopped doesn't get run.
@@ -133,7 +132,7 @@
 TEST_F(ThreadPoolTest, RecursiveTest) {
   Thread* self = Thread::Current();
   ThreadPool thread_pool(num_threads);
-  AtomicInteger count = 0;
+  AtomicInteger count(0);
   static const int depth = 8;
   thread_pool.AddTask(self, new TreeTask(&thread_pool, &count, depth));
   thread_pool.StartWorkers(self);