HashMap VS HashSet Java: In this article, we will discuss the difference between HashMap and HashSet Java classes in detail i.e.; HashMap VS HashSet Java.
HashMap VS HashSet Java
| HashMap | HashSet |
| It implements Map interface | It implements Set interface |
| Used to store key-value pairs using put method example: hm.put(key, value); | Used to store only unique objects using add method example: hs.add(object); |
| It doesn’t allow duplicate keys but values can be duplicated | HashSet doesn’t allow duplicate objects |
| It allows a maximum of one null key but any number of NULL values allowed | HashSet allows a maximum of one null object to be added |
| It internally uses an array of Entry<K, V> objects | HashSet internally uses HashMap to store unique objects |
| Performance-wise, HashMap is faster than HashSet | Performance-wise, HashSet is slower than HashMap |
When to use HashMap?
- It stores key-value pairs which use a hashing technique to store key-value pairs where methods are NOT synchronized
- So, the search operation is faster with multiple threads access
- So, if a business requirement is to store key-value pairs for faster search operation or number of search operation on the basis of keys; without concerning concurrent access to the map
- Then, HashMap is the very apt choice
When to use HashSet?
- HashSet stores unique elements using the hashing technique
- So, the search operation is faster
- So, if the 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
If You Feel That we have missed something or you want to add anything about this topic then you are most welcome for that. you can send your article about HashMap VS HashSet to our mail address admin@softwaretestingo.com. if you want to contribute something to this SoftwareTestingo community then you can drop your information on this link.
