Something like 'contains any' for Java set?

Question

I have two sets, A and B, of the same type.

I have to find if A contains any element from the set B.

What would be the best way to do that without iterating

Answer 1

A good way to implement containsAny for sets is using the Guava Sets.intersection().

containsAny would return a boolean, so the call looks like:

Sets.intersection(set1, set2).isEmpty()

This returns true iff the sets are disjoint, otherwise false. The time complexity of this is likely slightly better than retainAll because you dont have to do any cloning to avoid modifying your original set.