public   class  Server  extends  Thread
{
     public   void  run() 
    {
         try 
        {
            Properties props =  new  Properties();
            FileInputStream in
                    =  new  FileInputStream("database.properties");
            props.load(in);
            in.close();

            String port = props.getProperty("socket.port");
             int  i =  1 ;
            ServerSocket s =  new  ServerSocket(Integer.parseInt(port));
             for  (;;)
            {
                Socket incoming = s.accept( );
                
                /*JOptionPane.showMessageDialog(null,
				"Подключение " + i, "Новое подключение",
				JOptionPane.INFORMATION_MESSAGE);*/

                Thread t =  new  ThreadedHandler(incoming);
                t.start();
                i++;
            } 
                        
        }
         catch  (Exception e)
        {
            JOptionPane.showMessageDialog( null ,
				e.getMessage(), "Ошибка прослушивания порта",
				JOptionPane.ERROR_MESSAGE);
        }
    }
}

 class  ThreadedHandler  extends  Thread
{
    public  ThreadedHandler(Socket i)
   {
       incoming = i;
   }

    public   void  run()
   {
        try 
       {
           BufferedReader in =  new  BufferedReader
             ( new  InputStreamReader(incoming.getInputStream()));
           PrintWriter out =  new  PrintWriter
                 (incoming.getOutputStream(), true /* autoFlush */);

            boolean  done = false;

            while  (!done)
           {
               String line = in.readLine();

                if  (line !=  null )
               {
                   ...
                   читаем запрос и формируем ответ тут
                   ...
               }
           }
           incoming.close();

       }
        catch  (Exception e)
       {
           JOptionPane.showMessageDialog( null ,
                    e.getMessage(), "Ошибка обмена данными",
                    JOptionPane.ERROR_MESSAGE);
       }
   }
     private  Socket incoming;
}

 import  javax.swing.*;
 import  java.awt.*;
 import  java.awt.event.ActionListener;
 import  java.awt.event.ActionEvent;
 import  java.io.BufferedReader;
 import  java.io.InputStreamReader;
 import  java.io.PrintWriter;
 import  java.net.Socket;
 import  java.net.ServerSocket;

 public   class  SocketClientFrame  extends  JFrame
{
     public  SocketClientFrame()
    {
        setTitle("Сокет клиент");
        Container contentPane = getContentPane();
        Toolkit kit = Toolkit.getDefaultToolkit();
        Dimension screenSize = kit.getScreenSize();
         int  screenHeight = screenSize.height;
         int  screenWidth = screenSize.width;
        setLocation((screenWidth - WIDTH) /  2 , (screenHeight - HEIGHT) /  2 );
        setSize(WIDTH, HEIGHT);

         final  JTextArea textArea =  new  JTextArea( 7 ,  20 );
        JScrollPane scrollPane =  new  JScrollPane(textArea) ;
        textArea.setLineWrap(true);
        contentPane.add(scrollPane, BorderLayout.NORTH);

        JPanel bPan =  new  JPanel();
        contentPane.add(bPan, BorderLayout.SOUTH);

        JButton connBtn =  new  JButton("Подключиться");
        bPan.add(connBtn);
        connBtn.addActionListener( new 
                ActionListener()
                {
                     public   void  actionPerformed(ActionEvent evt)
                    {
                         try 
                        {
                            socket =  new  Socket("127.0.0.1",  8189 ); //Введи свое!!!

                            in =  new  BufferedReader
                                ( new  InputStreamReader(socket.getInputStream()));
                            out =  new  PrintWriter
                                (socket.getOutputStream(), true /* autoFlush */);
                        }
                         catch (Exception e)
                        {
                            JOptionPane.showMessageDialog( null ,
                                e.getMessage(), "Ошибка подключения к сокету!",
                                JOptionPane.ERROR_MESSAGE);
                        }
                    }
                });

        JButton sendBtn =  new  JButton("Отправить");
        bPan.add(sendBtn);
        sendBtn.addActionListener( new 
                ActionListener()
                {
                     public   void  actionPerformed(ActionEvent evt)
                    {
                        String text = textArea.getText();
                        out.println(text);
                        textArea.setText("");
                    }
                });

        JButton cnlBtn =  new  JButton("Выход");
        bPan.add(cnlBtn);
        cnlBtn.addActionListener( new 
                ActionListener()
                {
                     public   void  actionPerformed(ActionEvent evt)
                    {
                        System.exit( 0 );
                    }
                });

    }
     private  Socket socket;
     private  PrintWriter out;
     private  BufferedReader in;
     private   static   final   int  WIDTH =  500 ;
     private   static   final   int  HEIGHT =  200 ;

}

 import  javax.swing.*;

 public   class  SocketClient
{
      public   static   void  main(String[] args)
     {
         SocketClientFrame client =  new  SocketClientFrame();
         client.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         client.setVisible(true);
     }

}

 public   static   void  main(String[] args)
    {
            try 
           {
               Server consolServer =  new  Server();
               consolServer.start();
           }
            catch  (Exception e)
           {
               JOptionPane.showMessageDialog( null ,
                       e.getMessage(), "Ошибка при запуске сервера!",
                       JOptionPane.ERROR_MESSAGE);
           }
    }