udpserver2.java

this a client server programming that send a message to server and acknowledgement from the server.

package helloworld;

// UDPServer.java
// A server program implementing UDP socket
import java.net.*; 
import java.io.*; 

public class UDPServer2{
    public static void main(String args[])
    {
		DatagramSocket aSocket = null;
		try{
	        System.out.println("start server...");
	        
	        aSocket = new DatagramSocket(6880); //create a datagram socket using port 6880
		    byte[] buffer = new byte[1000]; 
		    while(true){
				DatagramPacket request = new DatagramPacket(buffer, buffer.length); 
			
				aSocket.receive(request); 	//listening incoming request
				System.out.println("receive from : " + 
					request.getAddress().toString() + ":" + request.getPort() +
					" message - " + new String(request.getData()).trim());
				
				DatagramPacket reply = new DatagramPacket(request.getData(),
					request.getLength(), request.getAddress(), request.getPort());
				
				aSocket.send(reply);//sending a reply message to client
				System.out.println("reply to     : " + reply.getAddress() + ":" 
					+ reply.getPort() + "\n");
	        }
        }
        catch (SocketException e){
            System.out.println("Socket: " + e.getMessage()); 
        }
        catch (IOException e) {
            System.out.println("IO: " + e.getMessage());
        }
		//close socket
		finally{ if(aSocket != null) aSocket.close();}
    }
}