Index Out Of Bounds Exception in ArrayList while removing objects

Question

Platform: JCreator

I usually use for loops that count from the back because theoretically when removing they should collapse fine:

0123456789

removing even numbers:

i = 9: 0123456789
i = 8 //remove 8: 012345679
i = 7: 012345679
i = 6 //remove 6: 01234579

and so on

But I get this exception when the object is removed:

Exception in thread "AWT-EventQueue-0" java.lang.IndexOutOfBoundsException: Index: 3, Size: 3

for (int i = dArea.size() - 1; i >= 0; i--) {
    if (dArea.get(i).getOwn() == 1) {
        if (dArea.get(i).getSK() == 2) {
            if (dArea.get(i).getX() - dArea.get(i).getW() / 2 > 1350) {
                dArea.remove(i);
            }
            if (dArea.get(i).getX() + dArea.get(i).getW() / 2 < 0) {
                dArea.remove(i);
            }
            if (dArea.get(i).getY() - dArea.get(i).getH() / 2 > 685) {
                dArea.remove(i);
            }
            if (dArea.get(i).getY() + dArea.get(i).getH() / 2 < 0) {
                dArea.remove(i);
            }
        }
    }
}

Any ideas why and how to fix?

Answer 1

Try using else if instead of if .

Otherwise one iteration in your loop may delete more than one element (once for the 'w' check and once for the 'h' check).