gistfile1.java

public class FlushHandler extends ChannelOutboundHandlerAdapter {

    @Override
    public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {

        ctx.flush();
        System.out.println("Flushed");


    }
}

public class OutboundHandler extends ChannelOutboundHandlerAdapter {

    @Override
    public void bind(ChannelHandlerContext ctx, SocketAddress localAddress, ChannelPromise promise) throws Exception {

        System.out.println("Bind happened");
        System.out.println(localAddress);
        InetSocketAddress ipSocketAddress = new InetSocketAddress("255.255.255.255", 7686);
        ByteBuf byteBuf = Unpooled.copiedBuffer("QOTM?", CharsetUtil.UTF_8);
        DatagramPacket udpPacket = new DatagramPacket(byteBuf, ipSocketAddress);
        ctx.write(udpPacket);

    }

}

public class MyChannelInitializer extends ChannelInitializer {

    @Override
    protected void initChannel(Channel channel) throws Exception {
        ChannelPipeline pipeline = channel.pipeline();
        pipeline.addLast("SecondOutboundHandler", new FlushHandler());
        pipeline.addLast("FirstOutboundHandler", new OutboundHandler());

    }
}

public class Client {

    public static void main(String[] args) throws Exception {

        EventLoopGroup group = new NioEventLoopGroup();
        try {
            Bootstrap b = new Bootstrap();
            b.group(group)
                    .channel(NioDatagramChannel.class)
                    .option(ChannelOption.SO_BROADCAST, true)
                    .handler(new MyChannelInitializer());
            b.bind(7000);

        } finally {
            group.shutdownGracefully();
        }
    }
}