HashSet Java Class

Article by: Manish Methani

Last Updated: October 23, 2021 at 10:04am IST
39 sec read

What are Hash Sets?

HashSet java class is used to create a collection that uses a hash table for storage. Sets are used to remove duplicate elements from the list and that's the big advantage of Sets over List.

The important points about the HashSet Java class are:

HashSet stores the elements by using a mechanism called hashing.

HashSet contains unique elements only.

Difference between List and Set

A basic difference between a List and a Set in Java is that list in Java can contain duplicate elements whereas a Set in Java contains unique elements only.

Example:-

import java.util.*;

public class JavaHashSetsDemo {
  public static void main(String[] args)
  {
    String[] things = {"Apples","Mango","Strwaberry","Mango"};
    List list = Arrays.asList(things);
    
    System.out.printf("%s ", list);
    System.out.println();
    
    Set set = new HashSet(list);
    System.out.printf("%s ", set);
  }
  
}

Output:-

[Apples, Mango, Strwaberry, Mango] 
[Apples, Strwaberry, Mango]