Simple multicast

You will start by making an indeed small multicast server that just joins a group, listens to it and prints received messages to the screen. If you take a look at the Java doc, this should almost be a matter of copy and paste.

Hint: java.net.MulticastSocket

MultiServer.java

Now make a small multicast client that connects to the same IP and port, and sends a "Hello World" message. If you first start your server and then run the client, you should see the message appear on the server side.

MultiClient.java

Finally, you could enhance the utilities to become a small chat system where the messages are sent by multicast packets. However, be aware that multicast in not enabled in the networks of all commercial operators.