//AppServer.java   
  import   javax.swing.*;   
  import   java.util.*;   
  import   java.awt.*;   
  import   java.net.*;   
  import   java.io.*;   
    
  class   Customer   implements   Serializable   
  {   
  String   infoMessage;   
  String   sendMessage;   
  String   custName;   
  String   otherName;   
  Vector   nameList   =   new   Vector(1,   1);   
  int   custSign   =   0;   
  }   
    
  public   class   AppServer   extends   Thread   
  {   
  ServerSocket   server;   
  static   Vector   sumName   =   new   Vector(1,   1);   
  static   Vector   sumList   =   new   Vector(1,   1);   
    
  public   AppServer()   
  {   
  try   
  {   
  server   =   new   ServerSocket(1001);   
  System.out.println(server.toString());   
  }   
  catch   (IOException   e)   
  {   
  System.out.println("Cannot   start   the   thread   "   +   e);   
  }   
    
  System.out.println("Server   started.....");   
  this.start();   
  }   
    
  public   static   void   main(String   args[])   
  {   
  new   AppServer();   
  }   
    
  public   void   run()   
  {   
  try   
  {   
  while   (true)   
  {   
  Socket   client   =   server.accept();   
  sumName.addElement(client);   
  Connection   con   =   new   Connection(client);   
  System.out.println("From:"   +   client.toString()   +   "Connected");   
  }   
  }   
  catch   (Exception   e)   
  {   
  System.out.println("Cannot   listen   to   the   client   "   +   e);   
  }   
  }   
  }   
    
  class   Connection   extends   Thread   
  {   
  protected   Socket   netClient;   
  protected   ObjectInputStream   toServer;   
  protected   ObjectOutputStream   toClient;   
    
  public   Connection(Socket   client)   
  {   
  netClient   =   client;   
    
  try   
  {   
  toServer   =   new   ObjectInputStream(netClient.getInputStream());   
  }   
  catch   (IOException   e)   
  {   
  System.out.println("IO   Exception"   +   e);   
    
  try   
  {   
  netClient.close();   
  }   
  catch   (IOException   evt)   
  {   
  System.out.println("Cannot   closed"   +   evt);   
  }   
  }   
    
  this.start();   
  }   
    
  public   void   run()   
  {   
  Socket   socket;   
  Customer   temp;   
    
  try   
  {   
  while   (true)   
  {   
  temp   =   (Customer)   toServer.readObject();   
    
  if   (temp.custSign   ==   2)   
  {   
  AppServer.sumList.addElement(temp.custName);   
  temp.nameList   =   AppServer.sumList;   
  temp.infoMessage   =   ">   >   >   >   >   >   >   >   >   >   "   +   "Welcome   "   +   temp.custName   +   "   to   chat   room!"   +   "   <   <   <   <   <   <   <   <   <   <";   
  }   
    
  if   (temp.custSign   ==   3)   
  {   
  int   index   =   AppServer.sumList.indexOf(temp.custName);   
  AppServer.sumList.removeElementAt(index);   
  temp.nameList   =   AppServer.sumList;   
  System.out.println(temp.custName   +   "   Exit!");   
  AppServer.sumName.removeElementAt(index);   
  temp.infoMessage   =   ">   >   >   >   >   >   >   >   >   >   "   +   temp.custName   +   "   have   left!"   +   "   <   <   <   <   <   <   <   <   <   <";   
  }   
    
  if   (!temp.otherName.equals("")   &&   !temp.otherName.equals("everybody"))   
  {   
  if   (AppServer.sumList.contains(temp.otherName))   
  {   
  for   (int   i   =   0;   i   <   AppServer.sumName.size();   i++)   
  {   
  socket   =   (Socket)   AppServer.sumName.elementAt(i);   
  toClient   =   new   ObjectOutputStream(socket.getOutputStream());   
  toClient.writeObject((Customer)temp);   
  }   
  }   
  else   
  {   
  int   sum   =   AppServer.sumList.indexOf(temp.custName);   
  temp.sendMessage   =   "Sorry,   "   +   temp.otherName   +   "have   left!";   
  temp.custSign   =   4;   
  socket   =   (Socket)   AppServer.sumName.elementAt(sum);   
  toClient   =   new   ObjectOutputStream(socket.getOutputStream());   
  toClient.writeObject((Customer)temp);   
  }   
  }   
  else   
  {   
  for   (int   i   =   0;   i   <   AppServer.sumName.size();   i++)   
  {   
  socket   =   (Socket)   AppServer.sumName.elementAt(i);   
  toClient   =   new   ObjectOutputStream(socket.getOutputStream());   
  toClient.writeObject((Customer)temp);   
  }   
  }   
  }   
  }   
  catch(Exception   e)   
  {   
  System.out.println("Exception   "   +   e);   
  }   
  }   
  }