void JNIHandles::destroy_weak_global(jobject handle) {

  {- -------------------------------------------
  (1) もし引数が NULL でなければ, JNIHandles::_weak_global_handles 内の該当する箇所に JNIHandles::_deleted_handle の値を書き込む.
      (引数が NULL の場合は何もしない)
      ---------------------------------------- -}

      if (handle != NULL) {
        assert(!CheckJNICalls || is_weak_global_handle(handle), "Invalid delete of weak global JNI handle");
        *((oop*)handle) = deleted_handle(); // Mark the handle as deleted, allocate will reuse it
      }
    }