Little problem I'm running with my applet

[Lightcraft]

Hello everyone. I am relatively new to Java and trying to get more experience. I've been recently handed an assignment that requires drawing 3 balls that bounce off each other and off the walls. It is also required that I created a button to change the direction of the red ball in a 45 degree clockwise angle. I have been able to accomplish this for the most part but it seems my coding for bouncing off each other messes up as I click the button to change the direction of the red ball. I am trying to think of why this is happning (if the actual incrementing I am doing for the balls is different then what the animation is showing me) and currently I am stumped. Any help to why or hints this is happening would be helpful.

I also know some of the methods I use are deprecated but the prof insisted on just using those methods for now so I had no choice. Also the balls only bounce off in a mirror reflection like fashion so there was no need to use vectors.

import java.lang.Math;
import java.awt.*;
import java.applet.*;
import javax.swing.*;
import javax.swing.event.*;
import java.awt.event.*;
import java.applet.AudioClip;

class Animation extends Thread{
  private JApplet app;
  private Color color;
  private int which;
  private int posit1x = 0;
  private int posit2x = 20;
  private int posit3x = 130;
  private int posit1y = 0;
  private int posit2y = 50;
  private int posit3y = 150;
  private int pause;
  private AudioClip a1,a2;
  private int in1x = 1;
  private int in1y = 1;
  private int in2x = 1;
  private int in2y = 1;
  private int in3x = 1;
  private int in3y = 1;
  private double c1,c2,c3;
  Animation(JApplet a, Color c, int which, int p) {
    color = c;
    app = a;
    pause = p;
    this.which = which;
  }
  public void run() {
    while (true) {
      posit1x += in1x;
      posit2x += in2x;
      posit3x += in3x;
      posit1y += in1y;
      posit2y += in2y;
      posit3y += in3y;
      try {
        Thread.sleep(pause);
      } catch (InterruptedException e) {}
      //Calculate distance between each ball to see if they need to bounce off each other
      c1 = (Math.pow((posit1x-posit2x),2) + Math.pow((posit1y-posit2y),2));
      c2 = (Math.pow((posit1x-posit3x),2) + Math.pow((posit1y-posit3y),2));
      c3 = (Math.pow((posit2x-posit3x),2) + Math.pow((posit2y-posit3y),2));
      a1 = app.getAudioClip(app.getDocumentBase(), "Audio1.au");
      a2 = app.getAudioClip(app.getDocumentBase(), "Audio2.au");
      //Coding to allow the balls to bounce off the walls 
      if (posit1x > app.size().width - 20|| posit1x < 0) {
        in1x = -in1x;
        a1.play();
      }if(posit1y > app.size().height - 45|| posit1y < 0){
        in1y = -in1y;
        a1.play();
      }if (posit2x > app.size().width -20|| posit2x < 0) {
        in2x = -in2x;
        a1.play();
      }if(posit2y > app.size().height - 45|| posit2y < 0){
        in2y = -in2y;
        a1.play();
      }if (posit3x > app.size().width - 20|| posit3x < 0) {
        in3x = -in3x;
        a1.play();
      }if(posit3y > app.size().height -45|| posit3y < 0){
        in3y = -in3y;
        a1.play();
        //Coding to allow balls to bounce off each other
      }if(Math.sqrt(c1) < 20){
        in1x = -in1x;
        in2x = -in2x;
        in1y = -in1y;
        in2y = -in2y;
        a2.play();
      }if(Math.sqrt(c2) < 20){
        in1x = -in1x;
        in3x = -in3x;
        in1y = -in1y;
        in3y = -in3y;
        a2.play();
      }if(Math.sqrt(c3) < 20){
        in2x = -in2x;
        in3x = -in3x;
        in2y = -in2y;
        in3y = -in3y;
        a2.play();
      }
     app.repaint();
      
    }
  }
  public void draw(Graphics g) {
    g.setColor(color);
    if (which == 1)
      g.fillOval(posit1x, posit1y, 20, 20); 
    if (which == 2)
      g.fillOval(posit2x, posit2y, 20, 20);
    if (which == 3)
      g.fillOval(posit3x , posit3y, 20, 20);
  }
  //X increment set method
  public void setx(int a){
    in1x = a;
  }
  //Y increment set method
  public void sety(int b){
    in1y = b;
  }
  //X get method
  public int getx(){
    return in1x;
  }
  //Y get method
  public int gety(){
    return in1y;
  }
  
}
class Animate extends JPanel {
  private JApplet a;
  private Animation t, t1, t2; 
  private Image img;          
  private Graphics gcopy;   
  private Double c1, c2; 
  private Color color;
  
  public void update(Graphics g) {
    paint(g);
  }
  public void paint(Graphics g) {
    //use method in A3 class to create references to each animation object
    t = A3.getAnimation("t");
    t1 = A3.getAnimation("t1");
    t2 = A3.getAnimation("t2");
    img = createImage(getWidth(), getHeight());
    gcopy = img.getGraphics();
    gcopy.setColor(Color.YELLOW);
    gcopy.fillRect(0, 0, getWidth(), getHeight());
    //Create double buffer to smooth out animation
    //and load each ball object into JPanel
    t.draw(gcopy);         
    t1.draw(gcopy);  
    t2.draw(gcopy);  
    g.drawImage(img, 0, 0, this);  
  }
}
public class A3 extends JApplet implements ActionListener{
  private Animate s;
  private Container c;
  private JButton b1;
  private JPanel j2;
  private static Animation t,t1,t2;
  public void init(){
    j2 = new JPanel();
    c = this.getContentPane();
    //Create a new Animate class to put into applet container
    s = new Animate();
    b1 = new JButton("TURN RED BALL 45 DEGREES");
    b1.addActionListener(this);
    j2.add(b1);
    c.setLayout(new BorderLayout());
    c.add(s, BorderLayout.CENTER);
    c.add(b1, BorderLayout.SOUTH);
  }
  //method to allow referencing to each ball object created in this class to JPanel for drawing
  public static Animation getAnimation(String b){
    if(b.equals("t")){
      return t;
    }if(b.equals("t1")){
      return t1;
    }if(b.equals("t2")){
      return t2;
    }
    return null;
  }
  public void start() {
    if (t == null) {
      t = new Animation(this, Color.RED,1,15);
      t.start();
    }if (t1 == null) {
      t1 = new Animation(this, Color.BLUE,2,15);
      t1.start();
    }if (t2 == null) {
      t2 = new Animation(this, Color.GREEN,3,15);
      t2.start();
    } 
  }
  public void stop() {
    if (t != null) {
      t.stop();
      t = null;
    } if (t1 != null) {
      t1.stop();
      t1 = null;
    }if (t2 != null) {
      t2.stop();
      t2 = null;
    }
  }
  
  public void actionPerformed(ActionEvent e){
    if(e.getSource()==b1){
      //Coding to program red ball behaviour each time the button is clicked based on direction the red ball is moving
      if(t.getx() == 1 && t.gety() == 1){
        t.setx(0);
      }else if(t.getx()== 0 && t.gety() == 1){
        t.setx(-1);
      }else if(t.getx()== -1 && t.gety() == 1){
        t.sety(0);
      }else if(t.getx() == -1 && t.gety() == 0){
        t.sety(-1);
      }else if(t.getx() == -1 && t.gety() == -1){
        t.setx(0);
      }else if(t.getx() == 0 && t.gety() == -1){
        t.setx(1);
      }else if(t.getx() == 1 && t.gety() == -1){
        t.sety(0);
      }else if(t.getx() == 1 && t.gety() == 0){
        t.sety(1);
      }
    }
  }
}

[camickr]

Well, I don't know the answer to your question, but I'm going to suggest you learn some Java basics first. For example:

a) use meaningfull variable names. What the heck are "a, t, t1, t2, c1, c2"? They mean nothing to me so I didn't even bother to try and follow the logic i your code.

b) Your painting code is wrong. You should never override update() and paint(), That is an old trick for when you a using AWT. For custom painting on a Swing component you should be overriding the paintComponent() method. Read the section from the Swing tutorial on "Custom Painting" for more information.