Design pattern with Swing Actions

import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.event.ActionEvent;

import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JToolBar;

public class ActionSample extends JFrame {
 
 private Action sampleAction;
 private Action exitAction;
 
 public ActionSample(){
  super("Using Actions");
  
  sampleAction = new AbstractAction(){
   public void actionPerformed(ActionEvent event){
    JOptionPane.showMessageDialog(ActionSample.this, "The sampleAction was invoked!");
    
    exitAction.setEnabled(true);
   }
  };
  
  sampleAction.putValue(Action.NAME, "Sample Action");
  
  sampleAction.putValue(Action.SHORT_DESCRIPTION, "A Sample Action");
  
  sampleAction.putValue(Action.MNEMONIC_KEY, new Integer('s'));
  
  exitAction = new AbstractAction(){
   public void actionPerformed(ActionEvent event){
    JOptionPane.showMessageDialog(ActionSample.this, "The exitAction was invoked");
    
    System.exit(0);
   }
  };
 
  exitAction.putValue(Action.NAME, "Exit");
  
  exitAction.putValue(Action.SHORT_DESCRIPTION, "Exit Application");
  
  exitAction.putValue(Action.MNEMONIC_KEY, new Integer('x'));
  
  exitAction.setEnabled(false);
  
  JMenu fileMenu = new JMenu("File");
  
  fileMenu.add(sampleAction);
  fileMenu.add(exitAction);
  fileMenu.setMnemonic('F');
  
  JMenuBar menuBar = new JMenuBar();
  menuBar.add(fileMenu);
  setJMenuBar(menuBar);
  
  JToolBar toolBar = new JToolBar();
  
  toolBar.add(sampleAction);
  toolBar.add(exitAction);
  
  JButton sampleButton = new JButton();
  sampleButton.setAction(sampleAction);
  
  JButton exitButton = new JButton(exitAction);
  
  JPanel buttonPanel = new JPanel();
  
  buttonPanel.add(sampleButton);
  buttonPanel.add(exitButton);
  
  Container container = getContentPane();
  container.add(toolBar, BorderLayout.NORTH);
  container.add(buttonPanel, BorderLayout.CENTER);  
 }
 
 public static void main(String args[]){
  ActionSample sample  = new ActionSample();
  sample.setDefaultCloseOperation(EXIT_ON_CLOSE);
  sample.pack();
  sample.setVisible(true);
 }

}