$//$ Program sets up a Server that receives connections from clients, sends

$//$ strings to the clients and receives string from the clients.

import java.io$.$IOException;

import java.io$.$ObjectInputStream;

import java.io$.$ObjectOutputStream;

import java.net.ServerSocket;

import java.net.Socket;

import java.awt.BorderLayout;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.util.ArrayList;

import java.util.concurrent.Executors;

import java.util.concurrent.ExecutorService;

import javax.swing.JFrame;

import javax.swing.JScrollPane;

import javax.swing.JTextArea;

import javax.swing.JTextField;

import javax.swing.SwingUtilities;

public class Server$2$ extends JFrame

$\{$

private JTextField enterField; $//$ text field to enter messages

private JTextArea display; $//$ text area to display messages

private JScrollPane scroller; $//$ scrollpane to scroll text area

private ArrayList$$ ClientRunnable $>$ clients; $//$ ArrayList of clients

private ExecutorService clientExecutor; $//$ to run clients

private ServerSocket server; $//$ server socket to accept connections

$//$ set up GUI

public Server$2()$

$\{$

super$("$Server$")$;

enterField $=$ new JTextField$()$; $//$ create enterField

enterField.setEnabled$($false$)$; $//$ disable editability

enterField.addActionListener$($

new ActionListener$()$

$\{$

$//$ send message to each client

public void actionPerformed$($ActionEvent event$)$

$\{$

for $($ClientRunnable eachClient : clients$)$

eachClient.sendData$($event$.$getActionCommand$())$;

enterField.setText$("")$; $//$ clear enterField

$\}//$ end actionPerformed

$\}//$ end anonymous inner class

$)$; $//$ end call to addActionListener

display $=$ new JTextArea$()$; $//$ create JTextArea

display.setEditable$($false$)$; $//$ disable editing

scroller $=$ new JScrollPane$($display$)$; $//$ add display to scrollpane

add$($enterField$,$ BorderLayout.NORTH$)$; $//$ add enterField

add$($scroller$,$ BorderLayout.CENTER$)$; $//$ add scrollpane

setSize$(300,150)$; $//$ set window size

setVisible$($true$)$; $//$ show window

clientExecutor $=$ Executors.newCachedThreadPool$()$; $//$ for clients

clients $=$ new ArrayList$$ ClientRunnable $>()$; $//$ initialize clients

$\}//$ end constructor Server$2$

$//$ set up and run server

public void runServer$()$

$\{$

try $//$ set up server and process connections

$\{$

server $=$ new ServerSocket$(5558,100)$; $//$ create server socket

ClientRunnable newClient; $//$ to hold new clients

$//$ accept connections and add clients to ArrayList

while $($true$)$

$\{$

displayMessage$("$Waiting for connection

$")$;

newClient $=$ new ClientRunnable$($server$.$accept$(),$

display, clients.size$())$; $//$ create a new client

clients.add$($newClient$)$; $//$ add client to ArrayList

clientExecutor.execute$($newClient$)$; $//$ run client

enterField.setEnabled$($true$)$; $//$ enable enterField

$\}//$ end while

$\}//$ end try

catch $($IOException ioException$)$

$\{$

ioException.printStackTrace$()$;

$\}//$ end catch

$\}//$ end method runServer

public void displayMessage$($final String message$)$

$\{$

SwingUtilities.invokeLater$($

new Runnable$()$

$\{$

public void run$()$

$\{$

display.append$($message$)$;

$\}//$ end method run

$\}//$ end anonymous inner class

$)$; $//$ end call to SwingUtilities.invokeLater

$\}//$ end method displayMessage

$//$ private inner class ClientRunnable manages each Client

private class ClientRunnable implements Runnable

$\{$

private int clientNumber; $//$ number of client in server

private Socket connection; $//$ connection to client

private ObjectOutputStream output; $//$ output stream to client

private ObjectInputStream input; $//$ input stream from client

private JTextArea display; $//$ displays messages

$//$ set up a client runnable

public ClientRunnable$($Socket socket, JTextArea displayArea,

int number$)$

$\{$

display $=$ displayArea; $//$ store the display

clientNumber $=$ number; $//$ store this client's number

connection $=$ socket; $//$ store connection to client

try $//$ obtain streams from Socket

$\{$

output $=$ new ObjectOutputStream$($

connection.getOutputStream$())$; $//$ get output stream

output.flush$()$; $//$ flush any data

$//$ get input stream

input $=$ new ObjectInputStream$($connection$.$getInputStream$())$;

sendData$("$Connection successful"$)$; $//$ notify of connection

displayMessage$("$

Connection $"+$ clientNumber $+$

$"$ received from: $"+$

connection.getInetAddress$().$getHostName

build a program that uses a client and server to implement a chat program. The requirements are as follows:

You MUST use approp