--- a/src/share/vm/oops/constantPool.cpp	Thu Apr 25 03:58:53 2013 -0700
+++ b/src/share/vm/oops/constantPool.cpp	Thu Apr 25 12:55:49 2013 -0700
@@ -40,6 +40,7 @@
 #include "runtime/init.hpp"
 #include "runtime/javaCalls.hpp"
 #include "runtime/signature.hpp"
+#include "runtime/synchronizer.hpp"
 #include "runtime/vframe.hpp"
 
 ConstantPool* ConstantPool::allocate(ClassLoaderData* loader_data, int length, TRAPS) {
@@ -69,7 +70,6 @@
 
   // only set to non-zero if constant pool is merged by RedefineClasses
   set_version(0);
-  set_lock(new Monitor(Monitor::nonleaf + 2, "A constant pool lock"));
 
   // initialize tag array
   int length = tags->length();
@@ -95,9 +95,6 @@
 void ConstantPool::release_C_heap_structures() {
   // walk constant pool and decrement symbol reference counts
   unreference_symbols();
-
-  delete _lock;
-  set_lock(NULL);
 }
 
 objArrayOop ConstantPool::resolved_references() const {
@@ -154,9 +151,6 @@
       ClassLoaderData* loader_data = pool_holder()->class_loader_data();
       set_resolved_references(loader_data->add_handle(refs_handle));
     }
-
-    // Also need to recreate the mutex.  Make sure this matches the constructor
-    set_lock(new Monitor(Monitor::nonleaf + 2, "A constant pool lock"));
   }
 }
 
@@ -167,7 +161,23 @@
   set_resolved_reference_length(
     resolved_references() != NULL ? resolved_references()->length() : 0);
   set_resolved_references(NULL);
-  set_lock(NULL);
+}
+
+oop ConstantPool::lock() {
+  if (_pool_holder) {
+    // We re-use the _pool_holder's init_lock to reduce footprint.
+    // Notes on deadlocks:
+    // [1] This lock is a Java oop, so it can be recursively locked by
+    //     the same thread without self-deadlocks.
+    // [2] Deadlock will happen if there is circular dependency between
+    //     the <clinit> of two Java classes. However, in this case,
+    //     the deadlock would have happened long before we reach
+    //     ConstantPool::lock(), so reusing init_lock does not
+    //     increase the possibility of deadlock.
+    return _pool_holder->init_lock();
+  } else {
+    return NULL;
+  }
 }
 
 int ConstantPool::cp_to_object_index(int cp_index) {
@@ -208,7 +218,9 @@
 
   Symbol* name = NULL;
   Handle       loader;
-  {  MonitorLockerEx ml(this_oop->lock());
+  {
+    oop cplock = this_oop->lock();
+    ObjectLocker ol(cplock , THREAD, cplock != NULL);
 
     if (this_oop->tag_at(which).is_unresolved_klass()) {
       if (this_oop->tag_at(which).is_unresolved_klass_in_error()) {
@@ -255,7 +267,8 @@
 
       bool throw_orig_error = false;
       {
-        MonitorLockerEx ml(this_oop->lock());
+        oop cplock = this_oop->lock();
+        ObjectLocker ol(cplock, THREAD, cplock != NULL);
 
         // some other thread has beaten us and has resolved the class.
         if (this_oop->tag_at(which).is_klass()) {
@@ -323,7 +336,8 @@
       }
       return k();
     } else {
-      MonitorLockerEx ml(this_oop->lock());
+      oop cplock = this_oop->lock();
+      ObjectLocker ol(cplock, THREAD, cplock != NULL);
       // Only updated constant pool - if it is resolved.
       do_resolve = this_oop->tag_at(which).is_unresolved_klass();
       if (do_resolve) {
@@ -619,7 +633,8 @@
                                      int tag, TRAPS) {
   ResourceMark rm;
   Symbol* error = PENDING_EXCEPTION->klass()->name();
-  MonitorLockerEx ml(this_oop->lock());  // lock cpool to change tag.
+  oop cplock = this_oop->lock();
+  ObjectLocker ol(cplock, THREAD, cplock != NULL);  // lock cpool to change tag.
 
   int error_tag = (tag == JVM_CONSTANT_MethodHandle) ?
            JVM_CONSTANT_MethodHandleInError : JVM_CONSTANT_MethodTypeInError;
@@ -780,7 +795,8 @@
   if (cache_index >= 0) {
     // Cache the oop here also.
     Handle result_handle(THREAD, result_oop);
-    MonitorLockerEx ml(this_oop->lock());  // don't know if we really need this
+    oop cplock = this_oop->lock();
+    ObjectLocker ol(cplock, THREAD, cplock != NULL);  // don't know if we really need this
     oop result = this_oop->resolved_references()->obj_at(cache_index);
     // Benign race condition:  resolved_references may already be filled in while we were trying to lock.
     // The important thing here is that all threads pick up the same result.