learning java AWT MenuBar Menu MenuItem菜单

import java.awt.*;

import java.awt.event.ActionListener;

import java.awt.event.KeyEvent;

import java.awt.event.WindowAdapter;

import java.awt.event.WindowEvent;

public class SimpleMenu {

    private Frame f  = new Frame("test");

    private MenuBar mb = new MenuBar();

    Menu file  =  new Menu("file");

    Menu edit  =  new Menu("edit");

    MenuItem crateItem = new MenuItem("create");

    MenuItem saveItem = new MenuItem("save");

    MenuItem exitItem = new MenuItem("exit",

            new MenuShortcut(KeyEvent.VK_X));

    CheckboxMenuItem autoWrap = new CheckboxMenuItem("autoWrap");

    MenuItem copyItem = new MenuItem("copy");

    MenuItem pasteItem = new MenuItem("paste");

    Menu format =  new Menu("format");

    /*ctrl + shift + / */

    MenuItem commentItem = new MenuItem("comment", new MenuShortcut(KeyEvent.VK_SLASH,true));

    MenuItem cancelItem = new MenuItem("cancelComment");

    private TextArea ta = new TextArea(,);

    public void init(){

        ActionListener menuListener = e -> {

          var cmd = e.getActionCommand();

          ta.append(" click " + cmd + " menu " + " \n ");

          if(cmd.equals("exit")){

              System.exit();

          }

        };

        commentItem.addActionListener(menuListener);

        exitItem.addActionListener(menuListener);

        file.add(crateItem);

        file.add(saveItem);

        file.add(exitItem);

        edit.add(autoWrap);

        edit.addSeparator();

        edit.add(copyItem);

        edit.add(pasteItem);

        format.add(commentItem);

        format.add(cancelItem);

        edit.add(new MenuItem("-"));

        edit.add(format);

        mb.add(file);

        mb.add(edit);

        f.setMenuBar(mb);

        f.addWindowListener(new WindowAdapter() {

            @Override

            public void windowClosing(WindowEvent e) {

                System.exit();

            }

        });

        f.add(ta);

        f.pack();

        f.setVisible(true);

    }

    public static void main(String[] args) {

        new SimpleMenu().init();

    }

}

output: