Question

I am making a game in which there will be many enemies on the screen. Here is part of the code so far:

private boolean update() {
    pIndex += cSpd;
    if (pIndex > path.length) return true;
    cX = path[pIndex].x;
    cY = path[pIndex].y;
    return false;
}

The problem is that if there are too many enemies/objects on screen, it will throw an exception. (I don’t know the precise amount of “too many,” but I will definitely need to have more than this amount.) Here is the exception:

Exception in thread "AWT-EventQueue-1" java.lang.ArrayIndexOutOfBoundsException: 3040
    at Game$GamePanel$Circle.update(Game.java:152)
    at Game$GamePanel$Circle.access$1(Game.java:149)
    at Game$GamePanel.paintComponent(Game.java:110)
    at javax.swing.JComponent.paint(Unknown Source)
    at javax.swing.JComponent.paintToOffscreen(Unknown Source)
    at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(Unknown Source)
    ...

I understand what it means. Line 152 is:

cX = path[pIndex].x;

However, this is confusing because the line right before it is:

if (pIndex > path.length) return true;

I don’t understand why this is happening. pIndex and the other variable aren’t static, so I don’t know how other Circles could affect it. Strangely, the index is always 3040 when it throws this exception. How can I fix this problem?

Answer 1

if (pIndex > path.length) return true;

That does not return if pIndex is exactly path.length, which is causing the exception.

The array index can only go upto array-length minus 1.