Sets comparison in Java

Forums:

HashSet<Integer> first = new HashSet<Integer>(Arrays.asList(1, 2));
HashSet<Integer> second = new HashSet<Integer>(Arrays.asList(1, 2));
HashSet<Integer> third = new HashSet<Integer>(Arrays.asList(1, 2, 3));

boolean isEqual = first.equals(second);
//isEqual is true

boolean isIntersects = first.stream().filter(i -> third.contains(i)).count() > 0;
//isIntersects is true

boolean isThirdSubsetOfFirst = first.containsAll(third);
//isSubset is false