JNI_ENTRY(jint, jni_MonitorEnter(JNIEnv *env, jobject jobj))

  {- -------------------------------------------
  (1) (DTrace のフック点)
      ---------------------------------------- -}

      DTRACE_PROBE2(hotspot_jni, MonitorEnter__entry, env, jobj);

  {- -------------------------------------------
  (1) (変数宣言など)
      ---------------------------------------- -}

      jint ret = JNI_ERR;

  {- -------------------------------------------
  (1) (DTrace のフック点)(リターン用) (See: DT_RETURN_MARK)
      ---------------------------------------- -}

      DT_RETURN_MARK(MonitorEnter, jint, (const jint&)ret);

  {- -------------------------------------------
  (1) ロック確保対象のオブジェクト(jobj)が NULL だった場合は, NullPointerException.
      ---------------------------------------- -}

      // If the object is null, we can't do anything with it
      if (jobj == NULL) {
        THROW_(vmSymbols::java_lang_NullPointerException(), JNI_ERR);
      }

  {- -------------------------------------------
  (1) (変数宣言など)
      ---------------------------------------- -}

      Handle obj(thread, JNIHandles::resolve_non_null(jobj));

  {- -------------------------------------------
  (1) ObjectSynchronizer::jni_enter() を呼び出して, ロックの確保を行う.
      ---------------------------------------- -}

      ObjectSynchronizer::jni_enter(obj, CHECK_(JNI_ERR));

  {- -------------------------------------------
  (1) リターン
      ---------------------------------------- -}

      ret = JNI_OK;
      return ret;
    JNI_END