setMnemonic and ActionListener won’t work on JMenu

Question

I’m following a Java tutorial but it isn’t working.

Question 1: why does the setMnemonic not work on my Mac, is it because Mac uses Option instead of Alt

Question 2: why does the action listener not work on my JMenu

The mnemonic did work on my JMenuItem, also actionlisyener worked on JMenuItem too, but not JMenu

I tried using UIManager.setLookAndFeel(UIManager.getCrossPlatformLookAndFeelClassName()); to use the windows feel and look on Mac

Thanks for any help!

I have this:

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;

public class MyFrame extends JFrame implements ActionListener {

    JMenu fileMenu;
    JMenu editMenu;
    JMenu helpMenu;

    JMenuItem loadItem;
    JMenuItem saveItem;
    JMenuItem exitItem;

    MyFrame() {

        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setSize(500, 500);
        this.setLayout(new FlowLayout());

        JMenuBar menuBar = new JMenuBar();

        fileMenu = new JMenu("File");
        editMenu = new JMenu("Edit");
        helpMenu = new JMenu("Help");

        loadItem = new JMenuItem("Load");
        saveItem = new JMenuItem("Save");
        exitItem = new JMenuItem("Exit");

        fileMenu.addActionListener(this);
        editMenu.addActionListener(this);
        helpMenu.addActionListener(this);

        fileMenu.setMnemonic(KeyEvent.VK_F); //alt+F打开file
        editMenu.setMnemonic(KeyEvent.VK_E);
        helpMenu.setMnemonic(KeyEvent.VK_H);

        fileMenu.add(loadItem);
        fileMenu.add(saveItem);
        fileMenu.add(exitItem);

        menuBar.add(fileMenu);
        menuBar.add(editMenu);
        menuBar.add(helpMenu);

        this.setJMenuBar(menuBar);
        this.setVisible(true);

    }

    @Override
    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == fileMenu) {
            System.out.println("File menu opened");
        }
        if (e.getSource() == editMenu) {
            System.out.println("Edit menu opened");
        }
        if (e.getSource() == helpMenu) {
            System.out.println("Help menu opened");
        }
    }
} 

I tried using UIManager.setLookAndFeel(UIManager.getCrossPlatformLookAndFeelClassName()); to use the windows feel and look on Mac

The tutorial was done on windows