A HashSet represents a set of elements(objects). It does not guarantee the order of elements. Also it does not allow the duplicate elements to be stored.

Syntax for HashSet class as:

class HashSet <T>

Note: Here, <T> represents the generic type parameter. It represents which type of elements are being stored into the HashSet. Suppose, we want to create a HashSet to store a group of Strings, then we can create the object as:

HashSet<String> hs=new HashSet<String>();

• HashSet();
• HashSet(int capacity);

Here, capacity is used to initialize the capacity of the hash set to the given integer value capacity. The capacity grows automatically as elements are added to the HashSet.
• HashSet(int capacity,float loadfactor);

Here,loadfactor determines the point where the capacity of HashSet would be increased internally.For example, the product of capacity and loadfactor

Following are the methods of Java HashSet class are as follows:

import java.util.*;
public class HashSetExample
{
    public static void main(String[] args)
    {
        //Creating HashSet to store strings
        HashSet hs=new HashSet();
        //store some string elements
       hs.add("HTML");
       hs.add("CSS");
       hs.add("Java Script");
       hs.add("Java");
       //view the HashSet
        System.out.println("Hash set= "+hs);
        //add an iterator to hs.
        Iterator it=hs.iterator();
        //display element by element using iterator
        System.out.println("Elements using iterator: ");
        while(it.hasNext())
        {
            String s=(String)it.next();
            System.out.println(s);
            //System.out.println(it.next());
        }//end of while loop
    }//end of main
}//end of class