[Java] intersection retainAll()

List<String> ss = new ArrayList<>(Arrays.asList(s.split(DELIMITER)));
List<String> ii = Arrays.asList(i.split(DELIMITER));
ss.retainAll(ii);

if (ss.size() == ii.size()) {
	return true;
}

https://jishushu.tistory.com/17

[Java] ArrayList의 출력/addAll()/ removeAll()/ retainAll()