Is there any method in the standard API to inverse retainAll()?

Question

Is there any method which does the following for me in one shot :

List<String> list1 = new ArrayList<String>(Arrays.asList("A","B","C","D"));
List<String> list2 = new ArrayList<String>(Arrays.asList("B","C","E","F"));
List<String> list3 = new ArrayList<String>();
for(String element : list2){
   if(!list1.contains(element))
   list3.add(element);
}

As a result list3 should contain elements "E" & "F".

Answer 1

Do you mean?

List<String> list3 = new ArrayList<String>(list2);
list3.removeAll(list1);

However, doing unions and intersections is usually best done using Sets rather than Lists. (And more efficiently)

Set<String> set3 = new LinkedHashSet<String>(set2);
set3.removeAll(set1);

Answer 2

Or with Guava's Sets.intersection():

Lists.newArrayList(Sets.intersection(ImmutableSet.of(list1), ImmutableList.of(list2)));