import java.net.DatagramPacket;
import java.net.DatagramSocket;
public class Main {
static final int BUFFERSIZE = 256;
public static void main(String[] args) throws Exception {
DatagramPacket pack = new DatagramPacket(new byte[BUFFERSIZE], BUFFERSIZE);
DatagramSocket sock = new DatagramSocket(7);
// echo back everything
while (true) {
sock.receive(pack);
sock.send(pack);
}
}
}