Both HashMap and HashSet are a hash-based collection in Java. They are not synchronized and cannot be shared between multiple threads. Both Hashmap and HashSet provide constant time performance for basic operations. They are different because their underlying class is different.
They are the two most popular collection classes. The most significant difference is that Hashmap is an imitation of the set interface, while HashSet is unique because it does not allow duplicates. Hashmap is a considerable value based upon data structure, and the methods it employs are different.
HashMap and HashSet are often used in computer languages and programming. The HashMap uses a hash code to map out the elements included in the interface. HashSet includes a hash table. The main difference is how the data is ordered, whether it is in a table like it is in the HashSet or on a map like it is in the HashMap.
HashMap is used more commonly and often than the HashSet. HashSet stores the information in the hash table. When concerning the null values, HashSet only permits the one null value. Even though the HashMap only permits the one null key, it permits as many null values as you want. HashMap can have duplicate values, but HashSet can’t.