comparing elements of two arrayList in java

Question

i got two String type arraylist ..one list containing “book1”, “book2”, “book3” and “book4”. And another arrayList contains “book1”, “book2”, “book3”. So, size of first list

Answer 1

You can transform the lists to sets, and then use Set.retainAll method for intersection between the different sets. Once you intersect all sets, you are left with the common elements, and you can transform the resulting set back to a list.