* Send multicast packets in Java

import java.net.*;
 
public class MCastSend {
 
    public static void main(String args[]) throws Exception 
	{
		if (args.length < 2) 
		{
			System.out.println("need group and port... exiting.");
			System.exit(1);
		}
		InetAddress group = InetAddress.getByName(args[0]);
		int port = Integer.parseInt(args[1]);
		MulticastSocket s = new MulticastSocket(16000);//port);
		s.setTimeToLive(5);
		s.joinGroup(group);
 
		byte buf[] = new byte[12];
		DatagramPacket msg = new DatagramPacket(buf, buf.length, group,port);
 
        byte i = 0;
		while (true) {
			buf[0] = i;
			buf[1] = (byte) 0;
			try {
			    System.out.println("Send " + buf[0]);
				s.send(msg);
				Thread.sleep(1000);
			}
			catch (Exception e) {}
			i++;
		}
    }
 
}

* Receive multicast packets in Java

import java.net.*;
 
public class MCastRecv {
 
    public static void main(String args[]) throws Exception {
 
		if (args.length == 0)
		{
			System.out.println("need group and port... exiting.");
			System.exit(1);
		}
		InetAddress group = InetAddress.getByName(args[0]);
		int port = Integer.parseInt(args[1]);
		MulticastSocket s = new MulticastSocket(port);
		s.joinGroup(group);
 
		byte buf[] = new byte[12];
		DatagramPacket msg = new DatagramPacket(buf, buf.length, group,port);
 
		int i = 0;
		while (true) {
		    try {
				s.receive(msg);
			    InetAddress from = msg.getAddress();
				int len = msg.getLength();
				byte inbuf[];
				inbuf = msg.getData();
				System.out.print("recvd mcast msg " + i++ + " from " + from.getHostAddress()
					+ " len = " +len + " ");
				int seq = inbuf[0];
				System.out.println(seq);
		    }
		    catch (Exception e) {}
		}
    }
 
}

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