Intersection and union of ArrayLists in Java

Question

Are there any methods to do so? I was looking but couldn\'t find any.

Another question: I need these methods so I can filter files. Some are AND filter

Answer 1

list1.retainAll(list2) - is intersection

union will be removeAll and then addAll.

Find more in the documentation of collection(ArrayList is a collection) http://download.oracle.com/javase/1.5.0/docs/api/java/util/Collection.html