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

class JMenuBarSample extends JFrame
                    implements ActionListener {
   JMenuBarSample() {
      JMenuBar menuBar = new JMenuBar();
      JMenu menuFile = new JMenu("File");
      JMenuItem menuOpen = new JMenuItem("Open");
      JMenuItem menuExit = new JMenuItem("Exit");
      JMenu menuView = new JMenu("View");
      JCheckBoxMenuItem menuTool
                      = new JCheckBoxMenuItem("Tool Bar");
      JMenu menuSize = new JMenu("Size");
      JMenuItem menuSizeLarge = new JMenuItem("Large");
      JMenuItem menuSizeSmall = new JMenuItem("Small");

      menuFile.setMnemonic(KeyEvent.VK_A);
      menuOpen.setMnemonic(KeyEvent.VK_B);
      menuExit.setMnemonic(KeyEvent.VK_C);
      menuView.setMnemonic(KeyEvent.VK_D);
      menuTool.setMnemonic(KeyEvent.VK_E);
      menuSize.setMnemonic(KeyEvent.VK_F);
      menuSizeLarge.setMnemonic(KeyEvent.VK_G);
      menuSizeSmall.setMnemonic(KeyEvent.VK_H);

      menuOpen.addActionListener(this);
      menuExit.addActionListener(this);
      menuTool.addActionListener(this);
      menuSizeLarge.addActionListener(this);
      menuSizeSmall.addActionListener(this);

      getRootPane().setJMenuBar(menuBar);
      menuBar.add(menuFile);
      menuFile.add(menuOpen);
      menuFile.add(menuExit);
      menuBar.add(menuView);
      menuView.add(menuTool);
      menuView.add(menuSize);
      menuSize.add(menuSizeLarge);
      menuSize.add(menuSizeSmall);

      setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      setTitle("JMenuBarを使ってメニューバーを表示");
      setSize(530, 120);
      setVisible(true);
   }
   public void actionPerformed(ActionEvent e) {
      System.out.println("["+ e.getActionCommand() +"]");
   }
   public static void main(String[] args) {
      new JMenuBarSample();
   }
}