Script Game Bola Pantulan (J2SE)

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

class GambarBolaAnimasi4 extends Canvas
{  
    int x;  
    int y;  
    int dX; 
    int dY;
    boolean move=true;
    int posisi;   
    int point;  
    String pointanda="";  
    int level=0;   
   
    public GambarBolaAnimasi4()  
    {      
        x=200; 
        y=100;    
        dX=5;    
        dY=5;   
        setBackground(Color.white); 
    }    
   
    public void paint(Graphics g)  
    {     
        g.setColor(Color.blue);  
        g.drawOval(x,y,10,10);
        if(move)     
        {        
            x+=dX;  
            y+=dY;      
            if(x<0)        
            {            
                dX=5+level;
            }       
            else if(x+10>getWidth())      
            {           
                dX=-5-level;   
            }         
            if(y<0)      
            {           
                dY=5+level;   
            }       
            else if(y+10>getHeight())  
            {       
                dY=-5-level;   
            }
            if(posisi==1 && y>130 && x>150) 
            {         
                move=false;        
                JOptionPane.showMessageDialog(null,"Selamat, Point anda "+ 
                        point,"Informasi",JOptionPane.INFORMATION_MESSAGE);
                System.exit(0);       
            }       
            if(posisi==2 && y>130 && x<150)    
            {          
                move=false;
                JOptionPane.showMessageDialog(null,"Selamat, Point anda "+
                        point,"Informasi",JOptionPane.INFORMATION_MESSAGE);    
                System.exit(0);       
            }       
            if((posisi==1 || posisi==2) && y>130)       
            {
              point=point+1;  
            }
}     
        String pointanda=Integer.toString(point);  
        System.out.println(pointanda);  
        if(point>5)     
        {       
            level=5;    
        }  
    } 
} 
class ProsesBolaAnimasi4 extends Thread
{   
    GambarBolaAnimasi4 picture; 
    public ProsesBolaAnimasi4(GambarBolaAnimasi4 obyekgambar)
   
    {     
        this.picture=obyekgambar; 
    }  
    public void run()  
    {      
        while(true) 
        {    
            picture.repaint();  
            try        
            {          
                sleep(50);     
            }      
            catch(Exception e)
            {     
            }     
        }   
    }
} 
public class Animasi4 extends JFrame
{  
    GambarBolaAnimasi4 gambar=new GambarBolaAnimasi4(); 
    ProsesBolaAnimasi4 proses=new ProsesBolaAnimasi4(gambar);
    JButton kiri=new JButton("<"); 
    JButton kanan=new JButton(">");  
    JLabel lblPoint=new JLabel("");   
    public Animasi4() 
    {      
        super("Game Sederhana dengan Level");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLocation(100,100);     
        setSize(310,220);
        proses.start();  
    }   
    void komponenVisual()  
    {    
        getContentPane().setLayout(null);
        getContentPane().add(gambar);    
        gambar.setBounds(0,0,300,140);
        getContentPane().add(kiri);    
        kiri.setBounds(0,140,150,25);  
        getContentPane().add(kanan);    
        kanan.setBounds(150,140,150,25);  
        getContentPane().add(lblPoint);   
        lblPoint.setBounds(150,165,150,20);  
        setVisible(true);  
    }    
    void aksiReaksi()
    {
        kanan.addKeyListener(new KeyAdapter() 
        {      
            public void keyPressed(KeyEvent k)    
            {        
                if(k.getKeyCode()==k.VK_RIGHT)
                {         
                    gambar.move=true;        
                    kiri.setVisible(true);   
                    kiri.requestFocus(true);     
                    kanan.setVisible(false);       
                    gambar.posisi=1;         
                }      
            } 
        });    
       
        kiri.addKeyListener(new KeyAdapter() 
        {       
            public void keyPressed(KeyEvent k)    
            {       
                if(k.getKeyCode()==k.VK_LEFT)  
                {              
                    gambar.move=true;      
                    kanan.setVisible(true);   
                    kanan.requestFocus(true);   
                    kiri.setVisible(false);      
                    gambar.posisi=2;            
                }      
            }    
        });   
    }  
    public static void main(String args[])   
    {     
        Animasi4 a4=new Animasi4(); 
        a4.komponenVisual();
        a4.aksiReaksi(); 
    }
}