A peer to peer chat using java

There are 2 parts to this project:
1.Client side
2.Server side

The server gets turned on.
Client 1 sends a datagram to the server through UDP.
The server pulls the ip and port from the datagram.
Client 2 sends a datagram to the server through UDP.
The server pulls the ip and port from the datagram.
The server sends a datagram to client 1 -> client1IP:client1PORT:client2IP:client2PORT:end
The server sends a datagram to client 2 -> client2IP:client2PORT:client1IP:client1PORT:end

Client 1 contacts Client 2 and sends a message "Can you hear me?"
Client 2 recieves the message and sends a message "I can hear you."

Client 2 contacts Client 1 and sends a message "Can you hear me?"
Client 1 recieves the message and sends a message "I can hear you."