Explain how a UDP client program (Table 25.13) sleeps until the response comes from the server.

Table 25.13 A simple UDP client program 1 import java.net.*; 2 import java.io.*: 3. 4 public class UDPClient 6. final int buffSize = ..; // Add buffer size DatagramSocket sock; String request; 7 8. String response; InetAddress servAddr; 10 11 int servPort; 12 13 UDPClient (DatagramSocket s, String sName, int sPort) 14 throws UnknownHostException 15 16 sock = s; 17 servAddr = InetAddress.getByName (sName); 18 servPort = sPort: 19 20 21 void makeRequest () 22 I/ Code to create the request string to be added here. void sendRequest ) try 29 { 30 byte [] sendBuff = new byte [buffSize]; 31 sendBuff = request.getBytes (0; 32 DatagramPacket sendPacket = new DatagramPacket (sendBuff, 33 sendBuff.length, servAddr, servPort); 34 sock.send(sendPacket); 35 36 catch (SocketException ex) 37 { 38 System.er.println ("SocketException in getRequest"); 39 40 41 42 void getResponse 0 43 { try 45 byte [] recvBuff = new byte [buffSize]; 47 DatagramPacket recvPacket = new DatagramPacket (recvBuff, buffSize); 48 sock.receive (recvPacket): 49 recvBuff = recvPacket.getData (); response = new String (recvBuff, 0, recvBuff.length); 51 catch (SocketException ex) 53 { System.er.println ("SocketException in getRequest"); 58 void useResponse 0 59 60 // Code to use the response string needs to be added here. 61 62 63 void close () 64 65 sock.close (); 66 67 68 public static void main (String [] args) throws IOException, SocketException 69 70 final int servPort ...; I/Add server port number 71 final String servName = ...; IIAdd server name 72 DatagramSocket sock = new DatagramSocket (); 73 UDPClient client = new UDPClient (sock, servName, servPort); 74 client.makeRequest (); client.sendRequest (); client.getResponse (); client.useResponse (): 75 76 77 78 client.close (); }// End of main 80 } // End of UDPClient class 79