Java for Programmers: Lab 15 Server Implementation

import java.net.ServerSocket;
import java.net.Socket;
import java.io.*;



 public class ChatServer {
  
   public static void main(String[] args) {
     try {
       int port = 2424;
       ServerSocket serverSock = new ServerSocket(port);
   
       while (true) {
        Socket sock = serverSock.accept();
        Thread t = new Thread(new ConnectionHandler(sock));
        t.start();
        }
      }
    catch(IOException e) {
      e.printStackTrace();
     }
  }
}


import java.net.Socket;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.io.OutputStreamWriter;
import java.util.Vector;
import java.util.Iterator;
                    
public class ConnectionHandler implements Runnable {
  Socket sock;
  static Vector list = new Vector();
  BufferedReader br;
  PrintWriter pw;
 public void run() {
   try {
     br = new BufferedReader(new InputStreamReader(sock.getInputStream()));
     pw = new PrintWriter(new OutputStreamWriter(sock.getOutputStream()));
 
    while(true) {
      String line = br.readLine();
 
      if ((line != null) && (line.endsWith("> bye"))) {
        System.exit(0);
       }
     System.out.println(line);
    broadcast(line);
    pw.flush();
   }
  }

  catch(Exception e) {
    e.printStackTrace();
   }
 }

  public void broadcast(String message) {
     for (Iterator iterator = list.iterator(); iterator.hasNext();) {
       ConnectionHandler connectionHandler = (ConnectionHandler) iterator.next();
       try {
         connectionHandler.pw.println(message + "\n");
         connectionHandler.pw.flush();
        }
       catch(Exception e) {
         list.remove(connectionHandler);
      }
    }
  }
 public ConnectionHandler(Socket sock) {
    this.sock = sock;
    list.add(this);
  }
}