On this document we will be showing a java example on how to use the iterator() method of HashSet Class. Basically this method returns an iterator to all the elements of the HashSet. Make a note that HashSet is unsorted thus the order of elements are pretty random, better watch out on this concept.

The HashSet as majority of the Collection classes make use of Generics such that if we have declared our set like HashSet<String> set = new HashSet<String>()  then the elements of inside our set is of type String otherwise a runtime error will be thrown.

Important notes for iterator() method:

  • specified by iterator in interface Iterable<E>
  • specified by iterator in interface Collection<E>
  • specified by iterator in interface Set<E>
  • specified by iterator in class AbstractCollection<E>

Method Syntax

public Iterator iterator()

Method Argument

Data Type Parameter Description

Method Returns

The iterator() method returns an Iterator over the elements in this set.


Requires Java 1.2 and up

Java HashSet iterator() Example

Below is a java code demonstrates the use of iterator() method of HashSet class. The example presented might be simple however it shows the behavior of the iterator() method.


import static java.lang.System.*;

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

 * This example source code demonstrates the use of  
 * iterator() method of HashSet class

public class HashSetIteratorExample {

	public static void main(String[] args) throws InterruptedException {

		// get the HashMap object from the method init()
		HashSet studentSet = init();

		// display the contents of our set
		Iterator it = studentSet.iterator();
		while (it.hasNext()) {


	private static HashSet init() {
		// declare the HashSet object
		HashSet studentSet = new HashSet<>();
		// put contents to our HashMap
		studentSet.add("Shyra Travis");
		studentSet.add("Sharon Wallace");
		studentSet.add("Leo Batista");
		return studentSet;


This example is a lot simpler than it looks. First we have a method init() which generally populates a HashSet object and return it. This method has been called by the main method which then list down all the contents of the student set object using the iterator method(). As we have said earlier that a set is unsorted and it does not follow any pattern in displaying the elements. There is no guarantee on how the elements are arranged on the Set object. This is a common mistakes for most of beginners in java programming.

Sample Output

Below is the sample output when you run the above example.

HashSet iterator() example output