Applet Game To Shot a Random Ball

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.JApplet;
import java.util.Random;

class shootApplet extends JApplet
{
	public void init()
	{
		setContentPane(new game() );
		
	}

 class game extends JPanel implements MouseListener
{
	private int width,height;
	int score=0;
	int x1,x2,x3,y1,y2,y3;
	int shot=0;
	int b_no[]=new int[3];
	int  x[]=new int[3];
	int  y[]=new int[3];
	private Ball ball;
	game()
	{
		setBackground(Color.yellow);
		
		ActionListener al=new ActionListener()
		{
			public void actionPerformed(ActionEvent ae)
				{
					if(ball!=null)
					{
						ball.generateCoord();
					}
					repaint();
				}
		};
		
	}
		

	public void mouseClicked(MouseEvent me)
	{
		int x,y;
		x=me.getX();
		y=me.getY();
		if(x==x1&&y==y1)
		{
			b_no[0]=0;
			score=score+5;
			shot++;
		}
		else if(x==x2&&y==y2)
		{
			b_no[1]=0;
			score=score+5;
			shot++;
		}
		else if(x==x3&&y==y3)
		{
			b_no[2]=0;
			score=score+5;
			shot++;
		}
				
	}
		
	public void mousePressed(MouseEvent me)	{}
		
	public void mouseReleased(MouseEvent me){}
	
	public void mouseEntered(MouseEvent me){}
		
	public void mouseExited(MouseEvent me){}
		
	public void paintComponent(Graphics g) 
	{
        super.paintComponent(g);  // Fill panel with background color, green.
        if (ball==null) 
		{
              // The first time that paintComponent is called, it assigns
             // values to the instance variables.
				width = getWidth();
				height = getHeight();
				ball=new Ball();
		}
	
		if (hasFocus())
		{
			g.setColor(Color.BLUE);
		}
		else
		{
			g.setColor(Color.RED);
			g.drawString("Target Balls",230,300);
			g.drawString("By Shilpa Dahiya",220,350);
			g.drawString("CLICK TO ACTIVATE", 210, 400);
			g.setColor(Color.GRAY);
		}
		g.drawRect(0,0,width-1,height-1);
		g.drawRect(1,1,width-3,height-3);
		g.drawRect(2,2,width-5,height-5);
		g.setColor(Color.BLACK);
		g.drawString("Score  " + score, 15, 24);
    }

	 class Ball
	{
			
			Random rand =new Random();
			int start;
			
			int z;
			
			Ball()
			{
				b_no[0]=1;
			    b_no[1]=1;
			    b_no[2]=1;
				this.start=1;
	    	}
			void generateCoord()
			{
				if(shot==3||start==1||y[0]>500||y[1]>500||y[2]>500)
				{
					shot=0;
					z=0;
					while(z<3)
					{
						x[z]=(int)(Math.random()*400);
						y[z]=(int)(Math.random()*400);
						z++;
						b_no[0]=1;
						b_no[1]=1;
						b_no[2]=1;
						
					}
				}
				
			}
		    
		
	
		void draw(Graphics g)
		{      
			if(b_no[0]!=0)
			{
				g.setColor(Color.red);
                g.drawOval(x[0],y[0],30,30);
                g.setColor(new Color(rand.nextInt(256), rand.nextInt(256), rand.nextInt(256))); 
				g.fillOval(x[0],y[0],30,30);
				x1=x[0];
				y1=y[0];
				
            }						 
			if(b_no[1]!=0)
			{
				g.setColor(Color.red);
				g.drawOval(x[1],y[1],30,30);
				g.setColor(new Color(rand.nextInt(256), rand.nextInt(256), rand.nextInt(256)));
 				g.fillOval(x[1],y[1],30,30);
				x2=x[1];
				y2=y[1];
            }
			if(b_no[2]!=0)
			{
				g.setColor(Color.red);
				g.drawOval(x[2],y[2],30,30);
				g.setColor(new Color(rand.nextInt(256), rand.nextInt(256), rand.nextInt(256))); 
				g.fillOval(x[2],y[2],30,30); 
				x3=x[2];
				y3=y[2];
			}
		
		}	
	}
	}
}