Merge "Minor optimization for CollectionUtils.mapNotNull"

    public static @NonNull <I, O> List<O> mapNotNull(@Nullable List<I> cur,

            Function<? super I, ? extends O> f) {

        if (isEmpty(cur)) return Collections.emptyList();

        final ArrayList<O> result = new ArrayList<>();

        List<O> result = null;

        for (int i = 0; i < cur.size(); i++) {

            O transformed = f.apply(cur.get(i));

            if (transformed != null) {

                result.add(transformed);

                result = add(result, transformed);

            }

        }

        return result;

        return emptyIfNull(result);

    }

    /**