What are the differences between Hashsets and Hashmaps?

Answer 1

They are entirely different constructs. A HashMap is an implementation of Map. A Map maps keys to values. The key look up occurs using the hash.

On the other hand, a HashSet is an implementation of Set. A Set is designed to match the mathematical model of a set. A HashSet does use a HashMap to back its implementation, as you noted. However, it implements an entirely different interface.

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HashSet

HashSet class implements the Set interface
In HashSet, we store objects(elements or values) e.g. If we have a HashSet of string elements then it could depict a set of HashSet elements: {“Hello”, “Hi”, “Bye”, “Run”}
HashSet does not allow duplicate elements that mean you can not store duplicate values in HashSet.
HashSet permits to have a single null value.
HashSet is not synchronized which means they are not suitable for thread-safe operations until unless synchronized explicitly.
HashMap

HashMap class implements the Map interface
HashMap is used for storing key & value pairs. In short, it maintains the mapping of key & value (The HashMap class is roughly equivalent to Hashtable, except that it is unsynchronized and permits nulls.) This is how you could represent HashMap elements if it has integer key and value of String type: e.g. {1->”Hello”, 2->”Hi”, 3->”Bye”, 4->”Run”}
HashMap does not allow duplicate keys however it allows having duplicate values.
HashMap permits single null key and any number of null values.
HashMap is not synchronized which means they are not suitable for thread-safe operations until unless synchronized explicitly.

Answer 2

Taken from Stack Exchange

Answer 3

The word set tells you it's a set.
The word map tells you there is mapping involved.

Answer 4

No problem!

Answer 5

😂 Okay... Is there any specific use for each, or can both be used interchangeably?

Answer 6

Thanks alot:)