SWING - skip from file to file and repaint everything?

Hi.
I have little problem. I want to erase everything from my screen and paint everything what is in another file.
I have something like that:
Menu:

Code:

---

package jumperSwing;
// DRAW MENU CONTENT IN PANEL

import java.awt.*;

import javax.swing.JPanel;
import javax.swing.JButton;

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class Menu extends JPanel implements ActionListener{

        private static final long serialVersionUID = 1L;
       
        private JButton start;
        private JButton exit;
       
        private BufferedImage MenuBG;
       
        public Menu() {
                super();
                setLayout(new FlowLayout(FlowLayout.CENTER, 15, 15));
       
                File imageFile = new File("images/sky.jpg");
                try {
                        MenuBG = ImageIO.read(imageFile);
                } catch (IOException e) {
                    System.err.println("Image Error");
                    e.printStackTrace();
                }
       
                start = new JButton("Start");
                exit = new JButton("Exit");
               
            start.addActionListener(this);
            exit.addActionListener(this);
               
                add(start);
                add(exit);
        }
       

       
          @Override
            public void actionPerformed(ActionEvent e) {
                Object click = e.getSource();
                if(click == start){
                        //skip to game
                }
                else if(click == exit)
                    System.exit(0);
            }
       
        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            Graphics2D g2d = (Graphics2D) g;
            g2d.drawImage(MenuBG, 0, 0, this);
        }
       
}

---

Game:

Code:

---

package jumperSwing;
// DRAW GAME CONTENT IN PANEL

import java.awt.*;

import javax.swing.JPanel;
import javax.swing.JButton;

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class Game extends JPanel implements ActionListener{

        private static final long serialVersionUID = 1L;

        private JButton jump;
       
        private BufferedImage GameBG;
       
        public Game(){
                super();
                setLayout(new FlowLayout(FlowLayout.CENTER, 15, 15));

       
                File imageFile = new File("images/sky2.jpg");
                try {
                        GameBG = ImageIO.read(imageFile);
                } catch (IOException e) {
                    System.err.println("Image Error");
                    e.printStackTrace();
                }
       
                jump = new JButton("Jump");
               
                jump.addActionListener(this);
               
                add(jump);

        }
       

       
          @Override
            public void actionPerformed(ActionEvent e) {
                Object click = e.getSource();
                if(click == jump){
                        // jump + points
                }
          }
       
        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            Graphics2D g2d = (Graphics2D) g;
            g2d.drawImage(GameBG, 0, 0, this);
        }
       
}

---

There is comment "//skip to game" in Menu, where I want put jump to Game file, but I have no idea how.
I tried to use this:

Code:

---

JPanel game = new Game();
add(game);

---

But It can't do anything.
Also tried:

Code:

---

validate();
repaint();
JPanel menu = new Menu();
add(menu);

---

But it just draw "jump" button in first free place(just like new button cause of flowlayout).
So. How can I stop and erase menu and paint game instead?

// Yea yea, I know maybe it doesnt make sense now to create 2 files with same things, but I just want to know how to do this and then I will change almost everything in Game ofc :P