[Ch15] More cleanup of the server. Plus using ExecutorService now.

package ch15;

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStreamReader;

import java.io.PrintWriter;

import java.net.ServerSocket;

import java.net.Socket;

import java.util.ArrayList;

import java.util.Iterator;

import java.util.concurrent.ExecutorService;

import java.util.concurrent.Executors;

public class SimpleChatServer {

    try {

      ServerSocket serverSock = new ServerSocket(5000);

      Broadcaster broadcaster = new Broadcaster();

      while (true) {

      while (!serverSock.isClosed()) {

        Socket clientSocket = serverSock.accept();

        PrintWriter writer = new PrintWriter(clientSocket.getOutputStream());

        broadcaster.addClient(writer);

        broadcaster.addClient(clientSocket);

        ClientHandler clientHandler = new ClientHandler(clientSocket, broadcaster);

        Thread t = new Thread(clientHandler);

        t.start();

        ExecutorService executorService = Executors.newSingleThreadExecutor();

        executorService.execute(clientHandler);

        System.out.println("got a connection");

        executorService.shutdown();

      }

    } catch (Exception ex) {

      ex.printStackTrace();

class ClientHandler implements Runnable {

  private BufferedReader reader;

  private Socket sock;

  private final Broadcaster broadcaster;

  public ClientHandler(Socket clientSocket, Broadcaster broadcaster) {

    this.broadcaster = broadcaster;

    try {

      sock = clientSocket;

      InputStreamReader isReader = new InputStreamReader(sock.getInputStream());

      InputStreamReader isReader = new InputStreamReader(clientSocket.getInputStream());

      reader = new BufferedReader(isReader);

    } catch (Exception ex) {

      ex.printStackTrace();

class Broadcaster {

  private final ArrayList<PrintWriter> clientOutputStreams = new ArrayList<>();

  void addClient(PrintWriter clientOutputStream) {

    clientOutputStreams.add(clientOutputStream);

  void addClient(Socket clientSocket) throws IOException {

    PrintWriter writer = new PrintWriter(clientSocket.getOutputStream());

    clientOutputStreams.add(writer);

  }

  public void tellEveryone(String message) {