Common elements in two lists

Question

I have two ArrayList objects with three integers each. I want to find a way to return the common elements of the two lists. Has anybody an idea how I can achiev

Answer 1

Using Java 8's Stream.filter() method in combination with List.contains():

import static java.util.Arrays.asList;
import static java.util.stream.Collectors.toList;

/* ... */

List list1 = asList(1, 2, 3, 4, 5);
List list2 = asList(1, 3, 5, 7, 9);

List common = list1.stream().filter(list2::contains).collect(toList());