Write an echo program with client and concurrent server using UDP.

Client program – ClientEcho.java

Java

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import java.net.*; import java.util.*;    public class ClientEcho {   public static void main( String args[] ) throws Exception   {     InetAddress add = InetAddress.getByName("snrao");                                                DatagramSocket dsock = new DatagramSocket( );     String message1 = "This is client calling";         byte arr[] = message1.getBytes( );       DatagramPacket dpack = new DatagramPacket(arr, arr.length, add, 7);     dsock.send(dpack);                                   // send the packet     Date sendTime = new Date();                          // note the time of sending the message        dsock.receive(dpack);                                // receive the packet     String message2 = new String(dpack.getData( ));     Date receiveTime = new Date( );   // note the time of receiving the message     System.out.println((receiveTime.getTime( ) - sendTime.getTime( )) + " milliseconds echo time for " + message2);   } }

Client program – ServerEcho.java

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import java.net.*; import java.util.*; public class ServerEcho {   public static void main( String args[]) throws Exception   {     DatagramSocket dsock = new DatagramSocket(7);     byte arr1[] = new byte[150];                                     DatagramPacket dpack = new DatagramPacket(arr1, arr1.length );          while(true)     {       dsock.receive(dpack);              byte arr2[] = dpack.getData();       int packSize = dpack.getLength();       String s2 = new String(arr2, 0, packSize);         System.out.println( new Date( ) + "  " + dpack.getAddress( ) + " : " + dpack.getPort( ) + " "+ s2);       dsock.send(dpack);     }   }           }