In this article, we will discuss difference between HashSet and LinkedHashSet classes in detail i.e.; HashSet v/s LinkedHashSet
Lets us move on and discuss key differences between these 2 Set implemented collection classes
HashSet v/s LinkedHashSet
|Uses hash table (acutally HashMap instance) to store element/objects||Uses combination of hash table + LinkedList to store element/objects|
|Doesn’t maintain insertion order i.e.; while iterating through HashSet, we will get items in random order||Since, it uses doubly-linked list to store elements, maintains insertion order|
|This is introduced in the original collection framework in Java 1.2 version||This is introduced in Java 1.4 version|
When to use HashSet?
- HashSet stores unique elements using hashing technique
- So, search operation is faster
- So, if business requirement is to store unique elements for faster search operation or more number of search operation without concerning insertion order
- Then, HashSet is the very apt choice
When to use LinkedHashSet?
- This is exactly same as that of HashSet, but underlying data structure to hold items is different
- It uses doubly-linked list which allows to hold items as per insertion order
- So, if business requirement is to store unique elements for faster search operation or more number of search operation concerning/maintaining insertion order
- Then, LinkedHashSet is the very apt choice which maintains insertion order
- So while iterating through LinkedHashSet, we will get items as per insertion order (as against random in HashSet)
Happy Coding !!
Happy Learning !!