Example Depot

// Create the lists List list1 = new ArrayList(); List list2 = new ArrayList(); // Add elements to the lists ... // Copy all the elements from list2 to list1 (list1 += list2) // list1 becomes the union of list1 and list2 list1.addAll(list2); // Remove all the elements in list1 from list2 (list1 -= list2) // list1 becomes the asymmetric difference of list1 and list2 list1.removeAll(list2); // Get the intersection of list1 and list2 // list1 becomes the intersection of list1 and list2 list1.retainAll(list2); // Remove all elements from a list list1.clear(); // Truncate the list int newSize = 2; list1.subList(newSize, list1.size()).clear();