private void init() {
/* initialize channel and pipeline factories */
ChannelFactory factory = new NioServerSocketChannelFactory(executor, executor);
bootstrap.setFactory(factory);
ChannelPipelineFactory pipelineFactory = new MinecraftPipelineFactory(this);
bootstrap.setPipelineFactory(pipelineFactory);
/* add shutdown hook */
Runtime.getRuntime().addShutdownHook(new Thread(new ServerShutdownHandler()));
}