Just a silly little test of Java multicasting.

Sender.java

import java.net.*;

class Sender {
  public static void main(String[] args) throws Throwable {
		MulticastSocket socket = new MulticastSocket(new InetSocketAddress(InetAddress.getByName("10.42.0.3"), 9999));
		InetAddress groupAddress = InetAddress.getByName("239.192.0.1");
		socket.send(new DatagramPacket(new byte[0], 0, groupAddress, 9999));
	}
}