Socket

import java.io.IOException;
import java.io.InputStream;
import java.net.ServerSocket;
import java.net.Socket;
public class JavaNet_SocketSever {

    /**
     * @param args
     * @throws IOException 
     */
    public static void main(String[] args) throws IOException {
        // TODO Auto-generated method stub
            ServerSocket ss=new ServerSocket(10003);
            Socket s=ss.accept();
            InputStream in=s.getInputStream();
            byte[] bt=new byte[1024];
            int len=in.read(bt);
            System.out.println(new String(bt,0,len));
            s.close();
            ss.close();
            }
}

import java.io.IOException;
import java.io.OutputStream;
import java.net.Socket;
public class JavaNet_SocketClient {
    /**
     * @param args
     * @throws IOException 
     */
    public static void main(String[] args) throws  IOException {
        // TODO Auto-generated method stub
        Socket s =new Socket("255.255.255.255", 10003);
        OutputStream out=s.getOutputStream();
        out.write("hello".getBytes());
        s.close();
    }
}