ช่วยทำ GUI เกมยิงบอล หน่อยนะครับ พอดีสร้างลูกบอลและตัวยิงได้แล้ว แต่อยากให้ยิงโดนแล้วลูกบอลหายไปแล้วคะแนนขึ้นด้วย

public class Ball implements Runnable{
    
    int x = 10, y = 35;
    int speed = 50;
    Color color;
    
    public Ball(int x, int speed, Color color){
        this.x = x;
        this.speed = speed;
        this.color = color;
    }
    
    public void paint(Graphics g){
        g.setColor(color);
        g.fillOval(x, y, 50, 50);
    }

    @Override
    public void run() {
        while((y+10) <= 400){
            y = y + 10;
            try{
                Thread.sleep(speed);
            } catch (Exception e){
                System.out.println("Message " + e);
            }
        }
    }
}

public class Shoot implements Runnable{

    int x = 10, y = 400;
    
    public Shoot(int x){
        this.x = x;
    }
    
    public void paint(Graphics g){
        g.setColor(Color.ORANGE);
        g.fillRect(x, y, 10, 20);
        
    }
    
    @Override
    public void run() {
       while(y-10 >= 10){
           y = y-10;
           try{
               Thread.sleep(100);
           } catch (Exception e){
               System.out.println("Message : " + e);
           }
       }
    }
}

public class BallGame extends javax.swing.JFrame implements Runnable, KeyListener{
    
    Ball[] ball = new Ball[5];
    int[] sball = {10, 100, 400, 300, 200};
    int[] speedBall = {100, 100, 100, 100 ,100};
    Color[] colorBall = {Color.BLACK, Color.BLUE, Color.RED, Color.GREEN, Color.MAGENTA};
    Thread thread; 
    
    int x = 10;
    
    Shoot shoot;
    
    public BallGame() {
        initComponents();
        thread = new Thread(this);
        thread.start();
        
        for(int i = 0; i < 5; i++){
            ball[i] = new Ball(sball[i], speedBall[i], colorBall[i]);
            new Thread(ball[i]).start();
        }
        
        this.addKeyListener(this);
    }
    
    public void paint(Graphics g){
        super.setSize(500, 500);
        g.setColor(Color.WHITE);
        g.fillRect(0, 0, getWidth(), getHeight());
        
        g.setColor(Color.BLACK);
        g.fillRect(x, 445, 50, 50);
        
        for(int i = 0; i < ball.length; i++){
            if(ball[i] != null){
                ball[i].paint(g);
            }
        }
            
        shoot.paint(g);
    }
    
    @Override
    public void run() {
        while(true){
            try{
                Thread.sleep(100);
            } catch (Exception e){
                System.out.println("Message " + e);
            }
            for(int i = 0; i < ball.length; i++){
                if(ball[i] != null && ball[i].y + 10 >= 400) {
                    ball[i] = null;
                }
            }
            repaint();
        }
    }
    
    @Override
    public void keyPressed(KeyEvent ke) {
       switch(ke.getKeyCode()){
           case 37 :    // Left
               if(x - 10 >= 10) x = x - 10;
               repaint();
               break;
           case 39 :    // Right
               if(x + 10 <= 400) x = x + 10;
               repaint();
               break;
           case 32 :    // Spcace
               shoot = new Shoot(x+20);
               new Thread(shoot).start();
               break;
       }
    }
}