import java.net.*;
import java.io.IOException;

public class UDPClient {

    public static void main(String args[]) {

        // args give message contents and server hostname

        DatagramSocket aSocket = null;

        try { 
            aSocket = new DatagramSocket();
            byte [] m = args[0].getBytes();
            InetAddress aHost = InetAddress.getByName(args[1]);
            int serverPort = 6789;
            DatagramPacket request = new DatagramPacket(m, args[0].length(), aHost, serverPort);
            aSocket.send(request);
            byte[] buffer = new byte[1000];
            DatagramPacket reply = new DatagramPacket(buffer, buffer.length);
            aSocket.receive(reply);
        } catch (SocketException e) {
            System.out.println("Socket: " + e.getMessage());
        } catch (IOException e) { 
            System.out.println("IO: " + e.getMessage());
        } finally {
            if(aSocket != null)
                aSocket.close();
        }

    }

}