import  java.io.ObjectInputStream;
 import  java.io.ObjectOutputStream;
 import  java.net.Socket;
 import  java.net.ServerSocket;

 public   class  Server {

     public   static   void  main(String[] args) {
         new  Server().start();
    }

     public   void  start() {
        ServerSocket ss =  null ;
         try  {
            ss =  new  ServerSocket( 65000 );
        }  catch  (Exception e) {
            e.printStackTrace();
            System.exit( 0 );
        }
         while  (true) {
             try  {
                 new  ServerTask(ss.accept()).start();
            }  catch  (Exception e) {
                e.printStackTrace();
                System.exit( 0 );
            }
        }
    }

     private   class  ServerTask  implements  Runnable {

         private  Socket s;
         private  Thread self;

         public  ServerTask(Socket s) {
             this .s = s;
            self =  new  Thread( this );
        }

         public   void  start() {
             this .self.start();
        }

         public   void  run() {
             try  {
                ObjectInputStream ois =  new  ObjectInputStream(s.getInputStream());
                CObject obj = (CObject) ois.readObject();
                System.out.println("Thread " +  this .self.getName() + ": a = " + obj.getA());
                obj =  new  CObject(obj.getA() *  2 );
                ObjectOutputStream oos =  new  ObjectOutputStream(s.getOutputStream());
                oos.writeObject(obj);
                oos.flush();
                s.close();
            }  catch  (Exception e) {
                e.printStackTrace();
                 if  (!s.isClosed()) {
                     try  {
                        s.close();
                    }  catch  (Exception ee) {
                        e.printStackTrace();
                    }
                }
            }
        }
    }
}

 import  java.net.Socket;
 import  java.net.InetSocketAddress;
 import  java.io.ObjectInputStream;
 import  java.io.ObjectOutputStream;

 public   class  Client {

     public   static   void  main(String[] args)  throws  Exception {
        Socket s =  new  Socket();
        s.connect( new  InetSocketAddress("localhost",  65000 ));
        ObjectOutputStream oos =  new  ObjectOutputStream(s.getOutputStream());

        oos.writeObject( new  CObject( 10 ));
        oos.flush();
        ObjectInputStream ois =  new  ObjectInputStream(s.getInputStream());
        CObject obj = (CObject) ois.readObject();
        System.out.println("a=" + obj.getA());
    }
}

 import  java.io.Serializable;

 public   class  CObject  implements  Serializable {

     private   int  a;

     public  CObject( int  a) {
         this .a = a;
    }

     public   int  getA() {
         return  a;
    }
}