Netty 4 Beta 3 issue

Question

I just started going trough the Netty 4 examples to see what is new and how to use it in an application. I started with the Discard Server tutorial. I wrote it and run and it worked. I could check via the telnet command. However based upon what is on the netty site I should be able to see something written on the console. But I could not see that though the app is running.

Also I have this warning message : WARNING: Your platform does not provide complete low-level API for accessing direct buffers reliably. Unless explicitly requested, heap buffer will always be preferred to avoid potential risk of getting OutOfMemoryError.

This is the code I have written:

/**
 * 
 */
package com.smsgh.Discard;

import java.net.InetSocketAddress;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;

/**
 * @author Arsene
 *
 */
public class DiscardServer {

    /**
     * 
     */
    public DiscardServer() {
    }

    public static void main(String[] args){

        // Instance of the Server bootstrap
        ServerBootstrap bootstrap = new ServerBootstrap();

        try{
            // Bootstrap group is used to handle incoming connections and handle the I/O of
            // those connections
            bootstrap.group(new NioEventLoopGroup(), new NioEventLoopGroup());

            // Set the factory
            bootstrap.channel(NioServerSocketChannel.class);

            // Add a child channel handler
            bootstrap.childHandler(new ChannelInitializer<SocketChannel>() {

                @Override
                protected void initChannel(SocketChannel ch) throws Exception {
                    ch.pipeline().addLast(new DiscardServerHandler());
                }
            });

            // add the options
            bootstrap.childOption(ChannelOption.TCP_NODELAY, true);
            bootstrap.childOption(ChannelOption.SO_KEEPALIVE, true);

            ChannelFuture future = bootstrap.bind(new InetSocketAddress(8889)).sync();
            future.channel().closeFuture().sync();
        }
        catch(Exception ex){
            ex.printStackTrace();
        }
        finally{
            bootstrap.shutdown();
        }
    }
}

and this is the server handler code:

/**
 * 
 */
package com.smsgh.Discard;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundByteHandlerAdapter;

/**
 * @author Arsene
 * 
 */
public class DiscardServerHandler extends ChannelInboundByteHandlerAdapter {

    /**
     * 
     */
    public DiscardServerHandler() {
    }

    /*
     * (non-Javadoc)
     * 
     * @see
     * io.netty.channel.ChannelInboundByteHandlerAdapter#inboundBufferUpdated
     * (io.netty.channel.ChannelHandlerContext, io.netty.buffer.ByteBuf)
     */
    @Override
    protected void inboundBufferUpdated(ChannelHandlerContext ctx, ByteBuf in)
            throws Exception {

        // Here we manipulate the data received
        while(in.isReadable()){
            System.out.println((char)in.readByte());
            System.out.flush();
        }
        in.clear();
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
        cause.printStackTrace();
        ctx.close();
    }
}

Can anyone tell me what went wrong? Thanx

Answer 1

I saw the issue. I did not add any encoder nor decoder of message coming in the pipeline.