DatagramSocket socket = new DatagramSocket(. . .) ;
DatagramPacket packet = new DatagramPacket(. . .) ;
//Récupération de données
byte[ ] receiveBuffer  = ...;
packet.setData(receiveBuffer) ;
socket.receive(packet) ;
//Envoie de données
byte[ ] sentBuffer = . . . ;
packet.setData(sentBuffer) ;
socket.send(packet) ;
socket.close() ;