I need to reverse this problem, code included

Question

Hello, I am trying to master Java and I have a long way to go. I am still trying to get a grip on the fundamentals. I have a program (the code is below) that I am trying to manipulate and get to do something a little different then it does. The program is basically used to teeach noobies (me) multithreading. This program (which I did not not write I have just been playing with it to learn different things) creates a ball (thread) and moves it 1000 times within the frame bouncing when it hits the wall on any side. I want to make it so the normal priority ball goes left to right and the high priority ball goes from top to bottom, but also when the button is pressed for either one to create a new ball it does not create one in the same spavce but a little bit over (the ball is sized to 15 so each time a new one is made it should move over the width of the ball + maybe 5 or 10) and by doing this i also have to make it so that if too many balls are made then it wont go off the screen but go backwards. I know I need to tweak the move method in class ball. I am trying to learn how to do this so I am not asking for an answer just guidence. If you can get me started I will figure it out and just post again as needed. Any help will be appreciated. Thankyou
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.util.*;
import javax.swing.*;
public class Bounce
   public static void main(String[] args)
      JFrame frame = new BounceFrame();
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.show();
class BounceFrame extends JFrame
   public BounceFrame()
      setSize(450,350);
      setTitle("Priority Threads");
      Container contentPane = getContentPane();
      canvas = new BallCanvas();
      contentPane.add(canvas, BorderLayout.CENTER);
      JPanel buttonPanel = new JPanel();
      addButton(buttonPanel, "Start-Normal Priority",
         new ActionListener()
               public void actionPerformed(ActionEvent evt)
                  addBall(Thread.NORM_PRIORITY, Color.red);
      addButton(buttonPanel, "Express-High Priroty",
         new ActionListener()
               public void actionPerformed(ActionEvent evt)
                  addBall(Thread.NORM_PRIORITY + 2, Color.black);
      addButton(buttonPanel, "Close",
         new ActionListener()
               public void actionPerformed(ActionEvent evt)
                  System.exit(0);
      contentPane.add(buttonPanel, BorderLayout.SOUTH);
   public void addButton(Container c, String title,
      ActionListener listener)
      JButton button = new JButton(title);
      c.add(button);
      button.addActionListener(listener);
   public void addBall(int priority, Color color)
      Ball b = new Ball(canvas, color);
      canvas.add(b);
      BallThread thread = new BallThread(b);
      thread.setPriority(priority);
      thread.start();
   private BallCanvas canvas;
class BallThread extends Thread
   public BallThread(Ball aBall) { b = aBall; }
   public void run()
      try
         for (int i = 1; i <= 1000; i++)
            b.move();
            sleep(5);
      catch (InterruptedException exception)
   private Ball b;
class BallCanvas extends JPanel
   public void add(Ball b)
      balls.add(b);
   public void paintComponent(Graphics g)
      super.paintComponent(g);
      Graphics2D g2 = (Graphics2D)g;
      for (int i = 0; i < balls.size(); i++)
         Ball b = (Ball)balls.get(i);
         b.draw(g2);
   private ArrayList balls = new ArrayList();
class Ball
   public Ball(Component c, Color aColor)
      canvas = c;
      color = aColor;
   public void draw(Graphics2D g2)
      g2.setColor(color);
      g2.fill(new Ellipse2D.Double(x, y, XSIZE, YSIZE));
   public void move()
      x += dx;
      y += dy;
      if (x < 0)
         x = 0;
         dx = -dx;
      if (x + XSIZE >= canvas.getWidth())
         x = canvas.getWidth() - XSIZE;
         dx = -dx;
      if (y < 0)
         y = 0;
         dy = -dy;
      if (y + YSIZE >= canvas.getHeight())
         y = canvas.getHeight() - YSIZE;
         dy = -dy;
      canvas.repaint();
   private Component canvas;
   private Color color;
   private int XSIZE=15;
   private int YSIZE=15;
   private int x = 0;
   private int y = 0;
   private int dx = 2;
   private int dy = 2;

Answer 1

I want to make it so the normal priority ball goes left to right and the high priority ball goes from top to bottom,You've only got the One Move() Method so all balls Move the same no matter what.
Maybe add some new Fields to the Ball Class and access them in your Move() method.
public Ball(Component c, Color aColor)
      canvas = c;
      color = aColor;
   }so maybe even:
public Ball( Component c, Color aColor ,int DX_forthisBall, int DY_forthisBall)with accessor methods for same
such as
public int getDX()
but also when the button is pressed for either one to create a new ball it does not create one in the same spavce but a little bit over (the ball is sized to 15 so each time a new one is made it should move over the width of the ball + maybe 5 or 10) Every Time You Create a New Ball
It has the same starting coordinates, because of your Code Design:
in the Canvas part:
private int x = 0;Modify your Constructor, to allow a Different initial position to be set, keep track of the Starting positions for each new Ball as you desire.
After a "Quick" look over your code, it seems all
Balls are created with various Colors and Priorities
However All are created Equal otherwise:
X=0 , Y = 0 ;dx =2 ; dy = 2; XSIZE = 15 ; YSIZE = 15
Perhaps you want to make it so that the Ball Class looks after
How Big each ball is and how fast and in which direction it moves.
So you would replace lines like:
if (x + XSIZE >= canvas.getWidth())
         x = canvas.getWidth() - XSIZE;
         dx = -dx;
      }with something like
Ball B; // this should refer to the currently being processed ball
// but is just here for example
if (x + B.getWidth() >= canvas.getWidth())
         x = canvas.getWidth() - B.getWidth();
         dx = -(Ball.getDX() );
      }SOme adaptation along those lines should do what you require