Remove all nulls in a single pass

[timtebeek]

Avoids repeatedly looping over the collection for as many nulls as are present. Delegates to Collection.removeIf with

    default boolean removeIf(Predicate<? super E> filter) {
        Objects.requireNonNull(filter);
        boolean removed = false;
        final Iterator<E> each = iterator();
        while (each.hasNext()) {
            if (filter.test(each.next())) {
                each.remove();
                removed = true;
            }
        }
        return removed;
    }

[tkvangorder]

Thanks Tim!

[timtebeek]

@knutwannheden has been doing some benchmarking; looks like it's faster to keep (and document) the original, as we only sparsely have mulitple nulls that trigger repeated traversals, whereas there's a higher tax on using removeIf.

[tkvangorder]

Interesting, so the overhead of creating the iterator + the fact that typically there are only one or two nulls means using remove(object) is quicker?

[timtebeek]

Yep! I agree it looks odd, but that's what we're finding. I'll close this PR; we can separately add a comment to indicate so.