Java HashSet isEmpty() Method

The isEmpty() method of Java HashSet class is used to check wheather HashSet contains an element or not. It returns true if the set contains element, otherwise returns false.

Syntax

Following is the declaration of isEmpty() method:

Parameter

This method does not accept any parameter.

Returns

The isEmpty() method returns true if this set contains no elements.

Exceptions

Compatibility Version

Java 1.2 and above

Example 1

import java.util.*;
public class HashSetIsEmptyExample1 {
	public static void main(String[] args) {
		//Creating HashSet Object
            HashSet<String> hset = new HashSet<String>();
            //Add elements into the Set
            hset.add("Welcome");
            hset.add("To");
            hset.add("JavaTpoint"); 
            //Print the HashSet Values
            System.out.println("HashSet Elements: "+hset); 
            //Check for the empty set
            System.out.println("Is the set empty: "+hset.isEmpty());
            //Clearing the set and Check for the empty set
            hset.clear();
            System.out.println("Is the set empty: "+hset.isEmpty());
	}
}

Test it Now

Output:

HashSet Elements: [Welcome, To, JavaTpoint]
Is the set empty: false
Is the set empty: true

Example 2

import java.util.*;
public class HashSetIsEmptyExample2 {
	public static void main(String[] args) {
		HashSet <Integer> hashSetObject = new HashSet <>();
		hashSetObject.add(45);
		hashSetObject.add(67);
		hashSetObject.add(98);
		//Checking whether HashSet is empty
		boolean b1 = hashSetObject.isEmpty();
		System.out.println("Is hash set empty?:- "+b1);
		System.out.println("HashSet Element: "+hashSetObject);
		//Clear HashSet
		hashSetObject.clear();
		boolean b2 = hashSetObject.isEmpty();
		System.out.println("Is hash set empty?:- "+b2);
		System.out.println("HashSet Element: "+hashSetObject);
	}
}

Test it Now

Output:

Is hash set empty?:- false
HashSet Element: [98, 67, 45]
Is hash set empty?:- true
HashSet Element: []

Example 3

import java.util.*;
public class HashSetIsEmptyExample3 {
	public static void main(String[] args) {
		//Get the HashMap object
		HashSet studentSet = init();				
		//Validate the set				
		if(studentSet.isEmpty()){
			System.out.println("student database is empty: "+studentSet);
		}
		else{
			System.out.println("student database has "+studentSet.size()+" names: "+studentSet);
		}
		studentSet.clear();
		if(studentSet.isEmpty()){
			System.out.println("student database is empty: "+studentSet);
		}
		else{
			System.out.println("student database has "+studentSet.size()+" names: "+studentSet);
		}
	}
	private static HashSet init() {
		//Create HashSet object
		HashSet<String> studentSet = new HashSet<>();
		//Add contents to the set
		studentSet.add("Rahul");
		studentSet.add("Mohan");
		studentSet.add("Karan");			
		return studentSet;
	}
}

Test it Now

Output:

student database has 3 names: [Rahul, Mohan, Karan]
student database is empty: []

Next TopicHashSet iterator() Method

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Java HashSet isEmpty() Method

Syntax

Parameter

Returns

Exceptions

Compatibility Version

Example 1

Example 2

Example 3

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