HashMap vs HashSet in Java
Learn the main differences between two of the most important data structures in Java
In Java, both HashSet and HashMap are data structures that use hashing to store and retrieve elements quickly. While both of these collections use a hash table to store their elements, there are some key differences between the two that developers need to be aware of when choosing which one to use.
HashSet
HashSet is a collection that stores unique elements, meaning it does not allow duplicate values. It is implemented using a hash table, which means the elements are stored in a hash table using their hash code as the key. This makes it very efficient to add, remove, and search for elements.
In a HashSet, the elements are not stored in any particular order. This means that when you iterate over the elements, the order in which you receive them is not guaranteed. HashSet does not provide any methods to retrieve the elements in a specific order.
Set is part of the Java Collection API, and different from List, it does not allow repeated values:
