UDP Chat - User Datagram Protocol - Networks & DBMS Lab - JAVA Program

Program:

// Client Program : client.java

import java.io.*;
import java.net.*;
 
class client
{
    public static void main(String args[]) throws Exception
    {
 
      BufferedReader clientRead =new BufferedReader(new InputStreamReader(System.in));
      DatagramSocket clientSocket = new DatagramSocket();
      InetAddress IP = InetAddress.getByName("127.0.0.1");
      byte[] sendbuffer = new byte[1024];
      byte[] receivebuffer = new byte[1024];
      System.out.print("\nClient: ");
      String clientData = clientRead.readLine();
      sendbuffer = clientData.getBytes();        
      DatagramPacket sendPacket =
      new DatagramPacket(sendbuffer, sendbuffer.length, IP, 9876);
      clientSocket.send(sendPacket);
      DatagramPacket receivePacket =
      new DatagramPacket(receivebuffer, receivebuffer.length);
      clientSocket.receive(receivePacket);
      String serverData = new String(receivePacket.getData());
      System.out.print("\nServer: " + serverData);
      clientSocket.close();
    }
}

// Server Program: server.java

import java.io.*;
import java.net.*;
 
class server
{
  public static void main(String args[]) throws Exception
    {
      DatagramSocket serverSocket = new DatagramSocket(9876);
      byte[] receivebuffer = new byte[1024];
      byte[] sendbuffer  = new byte[1024];
      while(true)
        {
          DatagramPacket recvdpkt = new DatagramPacket(receivebuffer, receivebuffer.length);
          serverSocket.receive(recvdpkt);
          InetAddress IP = recvdpkt.getAddress();
          int portno = recvdpkt.getPort();
          String clientdata = new String(recvdpkt.getData());
          System.out.println("\nClient : "+ clientdata);
          System.out.print("\nServer : ");
          BufferedReader serverRead = new BufferedReader(new InputStreamReader (System.in) );
          String serverdata = serverRead.readLine();
          sendbuffer = serverdata.getBytes();
          DatagramPacket sendPacket = new DatagramPacket(sendbuffer, sendbuffer.length, IP,portno);
          serverSocket.send(sendPacket);
        }
    }
} 

Output:

Terminal 1: (Client) 
nn@linuxmint ~ $ javac client.java
nn@linuxmint ~ $ java client

Client: hi...
  
Server: hello...nn@linuxmint ~ $


Terminal 2: (Server)
nn@linuxmint ~ $ javac server.java
nn@linuxmint ~ $ java server

Client : hi...

Server : hello...