ConcurrentModificationException when using iterator and iterator.remove()

Question

    private int checkLevel(String bigWord, Collection dict, MinMax minMax)
{
    /*value initialised to losing*/
    int value = 0; 
    if (minMax ==          


        

Answer 1

Something somewhere is modifying dict. I suspect it might be happening inside this call:

int value2 = checkLevel(removeWord(bigWord, str, i), dict, passin);
                                                     ^^^^

edit Basically, what happens is that the recursive call to checkLevel() modifies dict through another iterator. This makes the outer iterator's fail-fast behaviour to kick in.