Java HashSet isEmpty() Method with Examples

by Online Tutorials Library July 22, 2022

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 hset = new HashSet();              //Add elements into the Set              hset.add(“Welcome”);              hset.add(“To”);              hset.add(“TutorAspire”);               //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, TutorAspire ]  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  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 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

add(E e)clear()clone()contains(Object o)hashset isempty()iterator java remove(Object o)size()spliterator()

Java HashSet isEmpty() Method with Examples

Java HashSet isEmpty() Method

Syntax

Parameter

Returns

Exceptions

Compatibility Version

Example 1

Example 2

Example 3

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