Question

Hi
this code will return indexoutofboundsException and really I don’t know why?
I want to remove those objects from pointlist which are as the same as an object in the list.

    public void listOfExternalPoints(List<Point> list) {
    System.out.println(list.size());
    System.out.println(pointList.size());
    int n = pointList.size();
    for (int i = pointList.size() - 1; i >= 0; i--) {
        for (int j = 0; j < list.size(); j++) {
            if (pointList.get(i)==(list.get(j))) {
                pointList.remove(i);
                n--;
            }
        }
    }

}

Also the out put of println will be :

54
62

Also the exception:

Exception in thread "AWT-EventQueue-0" java.lang.IndexOutOfBoundsException: Index: 60, Size: 60
    at java.util.ArrayList.RangeCheck(ArrayList.java:547)
    at java.util.ArrayList.get(ArrayList.java:322)
    at ConvexHull.BlindVersion.listOfExternalPoints(BlindVersion.java:83)

thanks.

Answer 1

hey, you removed some elements from the list. So the list is smaller than it was at the beginning of the loop.

I suggest you to use:

pointList.removeAll(list)

Or an iterator.