<code java>
package chatMulticast;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.InetAddress;
import java.net.MulticastSocket;

public class CopyIn extends Thread {

	int chatPort = 0; 
	InetAddress chatAddress = null; 

	final int MAXBUF = 1024; 

	public  CopyIn(InetAddress ia, int port) {
		chatPort = port;
		chatAddress = ia; 
	}

	public void run() {
		MulticastSocket ds = null;
		try {
			ds = new MulticastSocket(chatPort);
		} catch (IOException e) {
			e.printStackTrace();
		}
		try {
			ds.joinGroup(chatAddress);
		} catch (IOException e) {
			e.printStackTrace();
		}
		DatagramPacket dp = null; 
		while (true) {
			try {
				dp = new DatagramPacket(new byte[MAXBUF], 0, MAXBUF);
				ds.receive(dp);
			} catch (IOException e) {
				e.printStackTrace();
			}
			String line =  new String(dp.getData());
			System.out.println("From "+dp.getAddress().getHostName()+": "+line);
		}
	}

}
</code>