code: @Override
  	public void close() throws Exception {
  		if (enterUnlessClosed()) {
  			try {
  				try {
  					// this class' own cleanup logic
  					resourceManagerLeaderElectionService.shutdown();
  					dispatcher.shutdownNow();
  				}
  				finally {
  					// in any case must we call the parent cleanup logic
  					super.close();
  				}
  			}
  			finally {
  				exit();
  			}
  		}
  	}
docs: ------------------------------------------------------------------------