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

• retainAll will modify your list
• Guava doesn't have APIs for List (only for set)

I found ListUtils very useful for this use case.

Use ListUtils from org.apache.commons.collections if you do not want to modify existing list.

ListUtils.intersection(list1, list2)