@Override
    public boolean containsAll(final Collection<?> arg) {
        for (final Object entry : arg) {
            if (indexOf(entry) < 0) {
                return false;
            }
        }
        return true;
    }
This is an extremely expensive implementation of
{@link Set#containsAll(Collection)}. It is implemented as O(n**2).
vespajlib/src/main/java/com/yahoo/collections/ArraySet.java