how to sort the Collection objects in Java?
What are the ways to remove duplicates from ArrayList?
What is WeakHashMap
What are the methods to make collection thread-safe?
What is the peek()of the Queue interface?
How to join multiple ArrayLists?
What is map. entry In Map?
What is the Properties file in collection?
Remove duplicates from ArrayList
Two ways to remove duplicates from ArrayList are:
HashSet: Developer can use HashSet to remove the duplicate element from the ArrayList. The drawback is it cannot preserve the insertion order.
LinkedHashSet: Developers can also maintain the order of insertion by using LinkedHashSet instead of HashSet.