Java HashSet size() Method

The size() method of Java HashSet class is used to get the number of elements in this HashSet (its cardinality).

Syntax

Following is the declaration of size() method:

Parameter

This method does not accept any parameter.

Returns

The size() method returns the number of elements present in the HashSet.

Exceptions

Compatibility Version

Java 1.2 and above

Example 1

import java.util.*;
public class HashSetSizeExample1 {
	public static void main(String[] args) {
		HashSet<String> set=new HashSet<String>();  
		set.add("Ravi");  
		set.add("Vijay");  
		set.add("Mohan");  
		set.add("Ajay");  
		//Print the HashSet
            System.out.println("HashSet: " + set);
            //Displaying the size of the HashSet
            System.out.println("The size of the set is: " + set.size());
	}
}

Test it Now

Output:

HashSet: [Vijay, Mohan, Ravi, Ajay]
The size of the set is: 4

Example 2

import java.util.*;
public class HashSetSizeExample2 {
	public static void main(String[] args) {
		HashSet <Integer> hashSetObject = new HashSet <>();
		hashSetObject.add(45);
		hashSetObject.add(-67);
		hashSetObject.add(98);
		int s = hashSetObject.size();  		
		System.out.println("Size of HashSet is: "+s);  		 
	}
}

Test it Now

Output:

Size of HashSet is: 3

Example 3

import java.util.*;
public class HashSetSizeExample3 {
	public static void main(String[] args) {
		//Get the HashSet object from the method init()
		HashSet studentSet = init();				
		//Print the size of the set
		int size = studentSet.size();
		System.out.println("Size of student database is: "+size);
	}
	private static HashSet init() {
		//Create HashSet object
		HashSet<String> studentSet = new HashSet<>();
		//Add contents in HashSet
		studentSet.add("Peter");
		studentSet.add("Watson");
		studentSet.add("Desuja");
		studentSet.add("Kevin");				
		return studentSet;
	}
}

Test it Now

Output: