code: public synchronized void stop() throws Exception {
  		if (this.serverChannel != null) {
  			this.serverChannel.close().awaitUninterruptibly();
  			this.serverChannel = null;
  		}
  		if (bootstrap != null) {
  			if (bootstrap.group() != null) {
  				bootstrap.group().shutdownGracefully();
  			}
  			bootstrap = null;
  		}
  	}
docs: Stops the artifact server.
  @throws Exception