JDK-6982173: Small problem causing thousands of wasted CPU hours

[Alan Snyder]

Right, I see that now.

Care must be exercised if this method is used on collections that
do not comply with the general contract for {@code Collection}.

So, what does this mean? Are we catering to incorrect implementations?



> On Feb 13, 2019, at 9:07 PM, Stuart Marks <stuart.marks at oracle.com> wrote:
> 
> On 2/13/19 7:22 PM, Alan Snyder wrote:
>> If we take this route, how about changing the parameter type to Iterable?
> 
> Won't work. Where I've ended up is that we need to iterate over "this" collection and, for each element, call contains() on the parameter. The AbstractCollection.removeAll() implementation does something like this:
> 
>    removeAll(Collection<?> c) {
>        for (Iterator<?> it = iterator(); it.hasNext();) {
>            if (c.contains(it.next())) {
>                it.remove();
>            }
>        }
>    }
> 
> Since we call contains() on the parameter, it has to be a Collection.
> 
> s'marks
>