我无法在gui中制作方括号。有人可以解释那里到底有什么问题吗？

Question

我正在尝试在gui上绘制矩形，但没有显示

我尝试使用repaint（）;和blackJackPanel.add（repaint（））;这是没有道理的，但绝望的。有2个类别，它们是菜单页面，我不会发布轮盘赌课程，因为它太长了。一切正常，除了二十一点课程，我无法让那个方格出现。

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.Rectangle2D;

public class BlackJack extends JPanel implements ActionListener {
    JPanel blackjackPanel = new JPanel();
    JMenu menu = new JMenu("Gry");
    JMenuItem menuRuletka = new JMenuItem("Ruletka");
    JMenuItem mainMenu = new JMenuItem("MainMenu");
    JMenuBar menuBar = new JMenuBar();

    public void entireBlackJackQueue(){
        panelConfig();
        menuConfiguration();

    }

    public void panelConfig(){
        blackjackPanel.setLayout(null);

    }
    public void menuConfiguration() {
        menuBar.setBounds(0, 0, 40, 20);
        menu.add(mainMenu);
        menu.add(menuRuletka);
        menuBar.add(menu);
        blackjackPanel.add(menuBar);

    }

    @Override
    public void actionPerformed(ActionEvent e) {

    }

    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        g.drawRect(230,80,10,10);
        g.setColor(Color.RED);
        g.fillRect(230,80,10,10);
    }
}

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 menu = new JMenu("Gry");
    JMenuItem menuRuletka = new JMenuItem("Ruletka");
    JMenuItem menuBlackJack = new JMenuItem("BlackJack");
    JFrame frame = new JFrame("Kasyno");
    Ruletka ruletka = new Ruletka();
    BlackJack blackJack = new BlackJack();
    JMenuBar menuBar = new JMenuBar();
    JPanel mainPanel = new JPanel();
    Main main = new Main();

    public MyFrame(){
        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        frame.setVisible(true);
        frame.setSize(900,600);
        menuConfiguration();
        mainFrameConfiguration();
        ruletka.entireRuletkaQueue();
        blackJack.entireBlackJackQueue();
        frame.setContentPane(mainPanel);
        frame.setResizable(false);


    }
    public void mainFrameConfiguration(){
        mainPanel.setLayout(null);
        mainPanel.add(menuBar);
    }
    public void menuConfiguration(){
        menuBar.setBounds(0,0,40,20);
        menuRuletka.addActionListener(this);
        menuBlackJack.addActionListener(this);
        menu.add(menuRuletka);
        menu.add(menuBlackJack);
        menuBar.add(menu);
        ruletka.mainMenu.addActionListener(this);
        blackJack.mainMenu.addActionListener(this);
        blackJack.menuRuletka.addActionListener(this);
        ruletka.menuBlackJack.addActionListener(this);
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        Object source = e.getSource();
        if(source==menuRuletka){
                frame.remove(mainPanel);
                frame.setContentPane(ruletka.ruletkaPanel);
                frame.validate();
                frame.repaint();
        }
        if(source==ruletka.mainMenu){
            frame.setContentPane(mainPanel);
            frame.remove(ruletka.ruletkaPanel);
            frame.validate();
            frame.repaint();
        }
        if(source==menuBlackJack){
            frame.setContentPane(blackJack.blackjackPanel);
            frame.remove(mainPanel);
            frame.validate();
            frame.repaint();
        }
        if(source==blackJack.mainMenu){
            frame.setContentPane(mainPanel);
            frame.remove(blackJack.blackjackPanel);
            frame.validate();
            frame.repaint();
        }
        if(source==blackJack.menuRuletka){
            frame.setContentPane(ruletka.ruletkaPanel);
            frame.remove(blackJack.blackjackPanel);
            frame.validate();
            frame.repaint();
        }
        if(source==ruletka.menuBlackJack){
            frame.setContentPane(blackJack.blackjackPanel);
            frame.remove(ruletka.ruletkaPanel);
            frame.validate();
            frame.repaint();
        }
    }
}

import java.awt.*;

public class Main {

    int saldo=1000;

    public void setSaldo(int saldo) {
        this.saldo = saldo;
    }

    public int getSaldo() {
        return saldo;
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                new MyFrame();
            }
        });


    }
}

if that square will be able to apear that would be great!