Java program - Online Address Book (server client application)

package com.mycompany.onlineaddressbook; import java.io.DataInputStream; import java.io.DataOutputStream; import java.io.IOException; import java.net.InetAddress; import java.net.ServerSocket; import java.net.Socket; import java.util.Date; public class MultiServerJPB1 { private static final int SERVER_PORT = 8765; public static void main(String[] args) { //createCommunicationLoop(); createMultithreadCommunicationLoop(); }//end main public static void createMultithreadCommunicationLoop() { int clientNumber = 0; try { ServerSocket serverSocket = new ServerSocket(SERVER_PORT); System.out.println("Server started on " + new Date() + "."); //listen for new connection request while(true) { Socket socket = serverSocket.accept(); clientNumber++; //increment client num //Find client's host name //and IP address InetAddress inetAddress = socket.getInetAddress(); System.out.println("Connection from client " + clientNumber); System.out.println("\tHost name: " + inetAddress.getHostName()); System.out.println("\tHost IP address: "+ inetAddress.getHostAddress()); //create and start new thread for the connection Thread clientThread = new Thread( new ClientHandler(clientNumber, socket, serverSocket)); clientThread.start(); }//end while } catch(IOException ex) { ex.printStackTrace(); } }//end createMultithreadCommunicationLoop public static void createCommunicationLoop() { try { //create server socket ServerSocket serverSocket = new ServerSocket(SERVER_PORT); System.out.println("Server started at " + new Date() + "\n"); //listen for a connection //using a regular *client* socket Socket socket = serverSocket.accept(); //now, prepare to send and receive data //on output streams DataInputStream inputFromClient = new DataInputStream(socket.getInputStream()); DataOutputStream outputToClient = new DataOutputStream(socket.getOutputStream()); //server loop listening for the client //and responding while(true) { String strReceived = inputFromClient.readUTF(); if(strReceived.equalsIgnoreCase("add")) { System.out.println("addin client"); outputToClient.writeUTF("client was added!"); } else if(strReceived.equalsIgnoreCase("quit")) { System.out.println("Shutting down server..."); outputToClient.writeUTF("Shutting down server..."); serverSocket.close(); socket.close(); break; //get out of loop } else { System.out.println("Unknown command received: " + strReceived); outputToClient.writeUTF("Unknown command. " + "Please try again."); } }//end server loop } catch(IOException ex) { ex.printStackTrace(); }//end try-catch }//end createCommunicationLoop }