Need urgent help with application please

Question

Hi i have a project for school. The application is a ball that bounces around in the frame and everytime it hits a wall it changes color and a popup menu is needed to change background color and to change the speed of the ball. I have so far got the ball to bounce and change color everytime it hits a wall and i also have a popup menu to change background color but im having trouble putting slow and fast modes on the popup menu. Below is my source code. Thread.sleep(10) is what determines the speed but i cant get it to be on the popup menu. Can somebody please help me. Thanks
code:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class WormX extends Panel implements ActionListener, Runnable{
private String[] colorNames =
{ "White", "Gray", "Red",
"Blue", "Black"};
private String[] speeds =
{"Slow", "Fast"};
private Color[] colors =
{ Color.white, Color.gray, Color.red,
Color.blue, Color.black };
private PopupMenu menu;
private PopupMenu menu1;
final int WIDTH = 280, HEIGHT = 230;
public static void main(String[] args) {
Frame f = new Frame();
f.addWindowListener(new java.awt.event.WindowAdapter() {
public void windowClosing(java.awt.event.WindowEvent e) {
System.exit(0);
WormX wx = new WormX();
wx.setSize(320,250); // same size as defined in the HTML APPLET
f.add(wx);
f.pack();
wx.init();
f.setSize(320,250 + 20); // add 20, seems enough for the Frame title,
f.show();
wx.start();
public void start(){
Thread t = new Thread(this);
t.start();
     PopupMenu popup;
int headx, heady, xinc, yinc;
Color color;
public void paint(Graphics g){
g.setColor(color);
g.drawString("OOO", headx, heady); //This is what the worm looks like.
public void run(){
while (true){
putWorm();
repaint();
try{
Thread.sleep(10); //This adjusts the speed of the worm
catch (InterruptedException e){
e.printStackTrace();
void checkWorm(){                      //checkworm is the coding for changing the colour of the worm
if ((headx >= WIDTH) || (headx <= 0)){
xinc *= -1;
changeColor();
else if ((heady >= HEIGHT) || (heady <= 0)){
yinc *= -1;
changeColor();
void changeColor(){    color = new Color((int)(Math.random() * 1677721));
void putWorm(){
headx += xinc;
heady += yinc;
checkWorm();
     public void init() {
xinc = 2;
yinc = 2;
color = Color.black; //This is the base colour of the worm
headx = (int)((Math.random() * WIDTH / 2) + WIDTH / 4);
heady = (int)((Math.random() * HEIGHT / 2) + HEIGHT / 4);
resize(WIDTH, HEIGHT);
     setBackground(Color.gray);
menu = new PopupMenu("Background Color");
enableEvents(AWTEvent.MOUSE_EVENT_MASK);
MenuItem colorName;
for(int i=0; i<colorNames.length; i++) {
colorName = new MenuItem(colorNames);
menu.add(colorName);
colorName.addActionListener(this);
menu.addSeparator();
add(menu);
menu1 = new PopupMenu("Speed");
enableEvents(AWTEvent.MOUSE_EVENT_MASK);
MenuItem speed;
for(int i=0; i<speeds.length; i++) {
speed = new MenuItem(speeds[i]);
menu.add(speed);
speed.addActionListener(this);
menu.addSeparator();
add(menu);
public void actionPerformed(ActionEvent event) {
setBackground(colorNamed(event.getActionCommand()));
repaint();
public void processMouseEvent(MouseEvent event) {
if (event.isPopupTrigger())
menu.show(event.getComponent(),
event.getX(), event.getY());
super.processMouseEvent(event);
private Color colorNamed(String colorName) {
for(int i=0; i<colorNames.length; i++)
if(colorNames[i].equals(colorName))
return(colors[i]);
return(Color.white);

Answer 1

I honestly don't know. I never had this Exception.
But look at the API:
http://java.sun.com/j2se/1.5.0/docs/api/java/lang/InterruptedException.html
Obviously, Java doesn't like what you do with your thread. Altogether, I'm not sure if your design isn't flawed. Basically, you pause your whole application regularly, so that it seems that you have a regular time flow. This is like doing slow motion on your DVD player by constantly pressing "play" and "pause".
Think about using the swing timer instead:
http://java.sun.com/j2se/1.5.0/docs/api/javax/swing/Timer.html
So, instead of binding your moving object to your main class, you can trigger it by the timer. Think about it.
Edit: As I see now, you DID catch the InterruptedException around the Thread.sleep(10) in your original code. Why did you do it in the first place, and why don't you now?
You can just catch the Exception, and leave it like that. However, when an Exception occurs regularly, it would be better to know why.
Editedit: Also, you declare the same class which is a panel als as a thread. AWT/Swing don't like it when create new Threads for the GUI, since AWT/Swing bring their own Thread for Event Handling. So, whatever you do with any kind of Threads, do it in some class which doesn't inherit from some visual component!