JAVA

how to build a java main menu

public class Screen extends JFrame implements ActionListener {
private static final long serialVersionUID = 1L;

int width, height;

JButton play = new JButton("play");
JButton settings = new JButton("settings");
JButton exit = new JButton("exit");
JButton mainMenu = new JButton("main menu");

CardLayout layout = new CardLayout();

JPanel panel = new JPanel();
JPanel game = new JPanel();
JPanel menu = new JPanel(); 

public Screen(int width, int height) {
    this.width = width;
    this.height = height;

    panel.setLayout(layout);        
    addButtons();

    setSize(width, height);
    setResizable(false);
    setLocationRelativeTo(null);
    setVisible(true);
    setTitle("BUILD YOUR EMPIRE");
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    requestFocus();

}

private void addButtons() {

    play.addActionListener(this);
    settings.addActionListener(this);
    exit.addActionListener(this);
    mainMenu.addActionListener(this);

    //menu buttons
    menu.add(play);
    menu.add(settings);
    menu.add(exit);

    //game buttons
    game.add(mainMenu);

    //background colors
    game.setBackground(Color.MAGENTA);
    menu.setBackground(Color.GREEN);

    //adding children to parent Panel
    panel.add(menu,"Menu");
    panel.add(game,"Game");

    add(panel);
    layout.show(panel,"Menu");

}

public void actionPerformed(ActionEvent event) {

    Object source = event.getSource();

    if (source == exit) {
        System.exit(0);
    } else if (source == play) {
        layout.show(panel, "Game");
    } else if (source == settings){

    } else if (source == mainMenu){
        layout.show(panel, "Menu");
    }

    }
}

creating a menu in java

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
class Menu implements ActionListener
{
    static JLabel text;
    //Driver function
    public static void main(String args[])
    {
	//Create a frame
	JFrame frame = new JFrame("Menu");
	frame.setSize(500,500);
	frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
	frame.setLayout(new FlowLayout());
	//Create an object
	Menu obj = new Menu();
	//Create a Menu
	JMenu menu = new JMenu("Select Here");
	//Create Menu Items
	JMenuItem item[] = new JMenuItem[5];
	for(int i=0;i<5;i++)
	{
	    item[i]=new JMenuItem("Item "+(i+1));
	    item[i].addActionListener(obj);
	    menu.add(item[i]);
	}
	//Create a menu bar
	JMenuBar mb=new JMenuBar();
	mb.add(menu);
	frame.setJMenuBar(mb);
	//Create the label
	text = new JLabel();
	frame.add(text);
	//Display the frame
	frame.setVisible(true);
    }
    //Function to display the menu item selected
    public void actionPerformed(ActionEvent e)
    {
	text.setText("Menu Item Selected : "+e.getActionCommand());
    }
}