JAVA CODE FOR UDP DATAGRAM-MESSAGE TRANSFER

PROGRAM: (UDP SERVER)

import java.io.*;

import java.net.*;

class UDPserver

{

   public static void main(String args[]) throws Exception

    {

       DatagramSocket serverSocket=new DatagramSocket(9876);

       byte[] receiveData=new byte[1024];

       byte[] sendData=new byte[1024];

     while(true)

     {

         DatagramPacket receivePacket=new                                  

         DatagramPacket(receiveData,receiveData.length);

         serverSocket.receive(receivePacket);

         String sentence=new String(receivePacket.getData());

         System.out.println("RECEIVED:"+sentence);

         InetAddress IPAddress=receivePacket.getAddress();

         int port=receivePacket.getPort();

         String capitalizedSentence=sentence.toUpperCase();

         sendData=capitalizedSentence.getBytes();

        DatagramPacket sendPacket=new     

        DatagramPacket(sendData,sendData.length,IPAddress,port);

        serverSocket.send(sendPacket);

  }

    }

       }

PROGRAM: (CLIENT)

import java.io.*;

import java.net.*;

class  UDPclient

{

     public static void main(String arg[]) throws Exception

      {

          BufferedReader inFromUser=new  BufferedReader(new    
          InputStreamReader(System.in));

          DatagramSocket clientSocket=new  DatagramSocket();

          InetAddress  IPAddress=InetAddress.getByName("localhost");

          byte[] sendData=new byte[1024];

byte[] receiveData=new byte[1024];

String sentence=inFromUser.readLine();

sendData=sentence.getBytes();

DatagramPacket sendPacket=new  DatagramPacket(sendData,sendData.length,IPAddress,9876);

clientSocket.send(sendPacket);

DatagramPacket receivePacket=new DatagramPacket(receiveData,receiveData.length);

clientSocket.receive(receivePacket);

String modifiedSentence=new String(receivePacket.getData());

System.out.println("FROM SERVER:"+ modifiedSentence);

clientSocket.close();

}

  }

  

OUTPUT: (SERVER)

RECEIVED:Hai

OUTPUT: (CLIENT)

Hai

FROM SERVER: hai