LeaderManager { public static LeaderManager getInstance() { return getInstance(getZookeeperAddress()); } private  LeaderManager(String zookeeperAddress); static LeaderManager getInstance(); static LeaderManager getInstance(String zookeeperAddress); LeaderLock takeLeadership(final String lockName, final LeaderCallback callback); void releaseLeadership(LeaderLock lock);  }
@Test public void test() { LeaderManager leaderManager = LeaderManager.getInstance(); assertNotNull(leaderManager); }