public class ListRetailAll {
public static void main(String[] args) {
List<Integer> list1 = new ArrayList<>(Arrays.asList(1, 2, 3, 4));
List<Integer> list2 = new ArrayList<>(Arrays.asList(3, 4, 5, 6));
list1.retainAll(list2);
System.out.println(list1);
List<Integer> list3 = new ArrayList<>(Arrays.asList(1, 2, 3, 4));
List<Integer> list4 = new ArrayList<>(Arrays.asList(3, 4, 5, 6));
List<Integer> intersection = list3.stream().filter(list4::contains).collect(Collectors.toList());
System.out.println(intersection);
}
}