Java tutorial
import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.InetAddress; public class Main { private final static int BUFSIZE = 20; public static void main(String args[]) { try { int port = 80; DatagramSocket ds = new DatagramSocket(port); byte buffer[] = new byte[BUFSIZE]; while (true) { DatagramPacket dp = new DatagramPacket(buffer, buffer.length); // Receive data ds.receive(dp); // Display address from the datagram packet InetAddress ia = dp.getAddress(); System.out.println(ia); buffer = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8, 9 }; dp.setData(buffer, 2, 5); } } catch (Exception e) { e.printStackTrace(); } } }