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.ServerSocket; import java.net.Socket; //Runnable class allows us to create a task //to be run on a thread public class ClientHandler implements Runnable { private Socket socket; //connected socket private ServerSocket serverSocket; //server's socket private int clientNumber; //create an instance public ClientHandler(int clientNumber, Socket socket, ServerSocket serverSocket) { this.socket = socket; this.serverSocket = serverSocket; this.clientNumber = clientNumber; }//end ctor //run() method is required by all //Runnable implementers @Override public void run() { //run the thread in here try { DataInputStream inputFromClient = new DataInputStream(socket.getInputStream()); DataOutputStream outputToClient = new DataOutputStream(socket.getOutputStream()); //continuously serve the client while(true) { String strReceived = inputFromClient.readUTF(); System.out.println("\n\t[[Command " + strReceived + " received from client " + clientNumber +"]]"); if(strReceived.equalsIgnoreCase("add")) { System.out.println("adding handlet client " + clientNumber); outputToClient.writeUTF("handler was added " + clientNumber + "!"); } 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 while } catch(IOException ex) { ex.printStackTrace(); }//end try-catch }//end run }//end ClientHandler