Android SoundManager和monitorenter以及monitorexit

我试着用monitorenter控制声音，monitorenter退出我使用的代码，但这对我不起作用这些ERORR显示：monitorenter不能解析为变量，monitorenter不能解析为变量，localObject不能解析为变量

 public static SoundManager getInstance()
 {
  monitorenter;
    try
    {
      if (_instance == null)
        _instance = new SoundManager();
      SoundManager localSoundManager = _instance;
      monitorexit;
      return localSoundManager;
    }
    finally
    {
      localObject = finally;
      monitorexit;
    }
    throw localObject;
}