Java HashSet.isEmpty() - Syntax & Examples

Java HashSetisEmpty Examples

In this tutorial, we will learn about the Java HashSet.isEmpty() method, and learn how to use this method to check if a HashSet is empty or not, with the help of examples.

isEmpty

HashSet.isEmpty() returns true if this HahSet contains no elements, and false if this HashSet contains atleast one element.

Syntax

The syntax of isEmpty() method is

HashSet.isEmpty()

Returns

The function returns boolean value of true or false.

Example 1 isEmpty

In this example, we will define an empty HashSet and programmatically check if the HashSet is empty or not using isEmpty() method.

Java Program

import java.util.HashSet;

public class Example {  
	public static void main(String[] args) {
		HashSet<String> hashSet = new HashSet<String>();
		
		boolean result = hashSet.isEmpty();
		System.out.println("Is HashSet empty?  " + result);
    }  
}

Output

Is HashSet empty?  true

Example 2 isEmpty Non-empty HashSet

In this example, we will define an HashSet with one element, and programmatically check if the HashSet is empty or not using isEmpty() method.

Java Program

import java.util.HashSet;

public class Example {  
	public static void main(String[] args) {
		HashSet<String> hashSet = new HashSet<String>();
		hashSet.add("a");
		
		boolean result = hashSet.isEmpty();
		System.out.println("Is HashSet empty?  " + result);
    }  
}

Output

Is HashSet empty?  false

Conclusion

In this Java Tutorial, we have learnt the syntax of Java HashSet.isEmpty() method, and also learnt how to use this method with the help of Java examples.