Java HashSet iterator() Method

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Description

The Java HashSet iterator() method is used to get an iterator over the elements in this set. The elements are returned in no particular order.

Declaration

Following is the declaration for java.util.HashSet.iterator() method.

public Iterator<E> iterator()

Parameters

NA

Return Value

The method call returns an Iterator over the elements in this set.

Exception

NA

Getting an Iterator from the HashSet of Integers Example

The following example shows the usage of Java HashSet iterator() method to iterate entries of the HashSet. We've created a HashSet object of Integer. Then few entries are added using add() method and then an iterator is retrieved using iterator() method and each value is printed by iterating through the iterator.

package com.tutorialspoint;

import java.util.HashSet;
import java.util.Iterator;

public class HashSetDemo {
   public static void main(String args[]) {
      
      // create hash set
      HashSet <Integer> newset = new HashSet <>();      

      // populate hash set
      newset.add(1); 
      newset.add(2);
      newset.add(3);  

      // create an iterator
      Iterator<Integer> iterator = newset.iterator(); 

      // check values
      while (iterator.hasNext()) {
         System.out.println("Value: "+iterator.next() + " ");  
      }
   }    
}

Output

Let us compile and run the above program, this will produce the following result.

Value: 1 
Value: 2 
Value: 3

Getting an Iterator from the HashSet of Strings Example

The following example shows the usage of Java HashSet iterator() method to iterate entries of the HashSet. We've created a HashSet object of String. Then few entries are added using add() method and then an iterator is retrieved using iterator() method and each value is printed by iterating through the iterator.

package com.tutorialspoint;

import java.util.HashSet;
import java.util.Iterator;

public class HashSetDemo {
   public static void main(String args[]) {
      
      // create hash set
      HashSet <String> newset = new HashSet <>();      

      // populate hash set
      newset.add("Learning"); 
      newset.add("Easy");
      newset.add("Simply");  

      // create an iterator
      Iterator<String> iterator = newset.iterator(); 

      // check values
      while (iterator.hasNext()) {
         System.out.println("Value: "+iterator.next() + " ");  
      }
   }    
}

Output

Let us compile and run the above program, this will produce the following result.

Value: Learning 
Value: Easy 
Value: Simply 

Getting an Iterator from the HashSet of Objects Example

The following example shows the usage of Java HashSet iterator() method to iterate entries of the HashSet. We've created a HashSet object of Student objects. Then few entries are added using add() method and then an iterator is retrieved using iterator() method and each value is printed by iterating through the iterator.

package com.tutorialspoint;

import java.util.HashSet;
import java.util.Iterator;

public class HashSetDemo {
   public static void main(String args[]) {
      
      // create hash set
      HashSet <Student> newset = new HashSet <>();      

      // populate hash set
      newset.add(new Student(1, "Julie")); 
      newset.add(new Student(2, "Robert"));
      newset.add(new Student(3, "Adam"));	  

      // create an iterator
      Iterator<Student> iterator = newset.iterator(); 

      // check values
      while (iterator.hasNext()) {
         System.out.println("Value: "+iterator.next() + " ");  
      }
   }    
}
class Student {
   int rollNo;
   String name;

   Student(int rollNo, String name){
      this.rollNo = rollNo;
      this.name = name;
   }

   @Override
   public String toString() {
      return "[ " + this.rollNo + ", " + this.name + " ]";
   }
}

Output

Let us compile and run the above program, this will produce the following result.

Value: [ 1, Julie ] 
Value: [ 2, Robert ] 
Value: [ 3, Adam ]