import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class DoublerMain {

    public static void main(String[] args) {
       
        Doubler buttonFrame = new Doubler();
        buttonFrame.setSize(350,120);
        buttonFrame.setLocation(250,100);
        buttonFrame.setVisible(true);
    }
}

class Doubler extends JFrame{
   
    int value = 1;
    
    public Doubler ()
    {
        JButton doubleButton = new JButton ("Double");
        JButton quitButton = new JButton("Quit");
        final JTextField doubleText = new JTextField ("Value:    1");
        
        JPanel buttons = new JPanel();
        buttons.setLayout (new FlowLayout());
     
        buttons.add (doubleButton);      
        buttons.add (quitButton);
        
        setTitle("Doubler Frame");
        setLayout(new BorderLayout());
        add(buttons, BorderLayout.SOUTH);
        add(doubleText, BorderLayout.NORTH);
  
        doubleButton.addActionListener (new ActionListener()
        {
            public void actionPerformed( ActionEvent e) 
            {
                value = value * 2;
                doubleText.setText("New value: " + value);
            }
        });  
        
        quitButton.addActionListener (new ActionListener()
        {
            public void actionPerformed( ActionEvent e) 
            {
                System.exit(1);
            }
        });   
    }
}