public class Server {

    public void run() throws InterruptedException {

        EventLoopGroup accepter = new NioEventLoopGroup();
        EventLoopGroup worker = new NioEventLoopGroup();

            ServerBootstrap b = new ServerBootstrap();
            b.group(accepter, worker)
            .channel(NioServerSocketChannel.class)
            .childHandler(new ChannelInitializer<SocketChannel>() {

                @Override
                protected void initChannel(SocketChannel s) throws Exception {
                    ChannelPipeline p = s.pipeline();
                    p.addLast(new Handler());
                }

            });

            ChannelFuture f = b.bind(43594).sync();

    }

    /**
     * @param args
     * @throws Exception
     */
    public static void main(String[] args) throws Exception {
        new Server().run();
    }
}

public class Handler extends ChannelInboundHandlerAdapter {

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) {
        ((ByteBuf) msg).release();
    }

    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) {
        ctx.flush();
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
        // Close the connection when an exception is raised.
        cause.printStackTrace();
        ctx.close();
    }

}