Question

I want to compare these two ArrayList:

public static ArrayList<List<String>> arrayList1 = new ArrayList<List<String>>();
public static ArrayList<List<String>> arrayList2 = new ArrayList<List<String>>();

If they have the same elements it will return true, otherwise false.

Answer 1

You can try using Apache commons CollectionUtils.retainAll method : Returns a collection containing all the elements in collection1 that are also in collection2.

ArrayList commonList = CollectionUtils.retainAll(arrayList1, arrayList2);

If the size of commonList is equal to　arrayList1　and arrayList2 you can say both the list are same.