How to print HashSet Elements in Java?

In this tutorial, we will learn ‘How to print HashSet elements’ in Java with some examples. It’s a very important concept in java or real word application developed using java.

HashSet:

-HashSet class is used to create a collection. A collection is an object that represents group of object.

-HashSet does not allow duplicate elements.

-HashSet allows null values. And it supports both homogeneous and heterogeneous elements.

-In HashSet we add/ insert element using add() method.

-It is an implementation of  hashing technique with array representation. So insertion order is not preserved. It stores the elements according hash code based order.

-In HashSet elements are stored according to the following:

There are 3 ways to print HashSet elements:

• Using reference variable(Directly by name): We can directly print HashSet elements using HashSet object reference variable. It will print complete HashSet element.

Import java.util.*;
Class HashSetDemo
{
    Public static void main(String args[])
    {	
        HashSet<Character> hs = new HashSet<>();
        hs.add(‘a’);
        hs.add(‘p’);
        hs.add(‘b’);
        System.out.println(hs);
    }
}

• Using Iterator() method: It is used iterate elements of a collection. It will print element one by one form the collection. By using this method we can perform both read & remove operations.

Iterator it = hs.iterator();
while(it.hashNext())
{
    System.out.println(hs.next());
}

• Using Enhanced for loop:  It is also used to print element one by one from the collection. It is introduced since JDK 1.5 version.

  for(Object o : hs)
  {
       System.out.println(o);
  }