BeginnersBook

  • Home
  • Java
    • Java OOPs
    • Java Collections
    • Java Examples
  • C
    • C Examples
  • C++
    • C++ Examples
  • DBMS
  • Computer Network
  • Python
    • Python Examples
  • More…
    • jQuery
    • Kotlin
    • WordPress
    • SEO
    • JSON
    • JSP
    • JSTL
    • Servlet
    • MongoDB
    • XML
    • Perl

Java – How to Sort a HashSet?

Last Updated: September 11, 2022 by Chaitanya Singh | Filed Under: java

As we know HashSet doesn’t sort elements, in fact it displays them in random order. While dealing with HashSet we may come across a situation where we need to sort it explicitly. we need to write a logic to sort them when required. In this article we are going to see an example where we are sorting a HashSet using two different methods.

/* Program to Sort a HashSet using two different 
 * methods. 
 * Method 1:By using List interface
 * Method 2:By using TreeSet
 */
import java.util.Collections;
import java.util.ArrayList;
import java.util.List;
import java.util.HashSet;
import java.util.TreeSet;

public class SortingHashSetDemo {
   public static void main(String args[]) {

       HashSet<String> fruits = new HashSet<String>();
           
       fruits.add("Orange");
       fruits.add("Apple");
       fruits.add("Banana");
       fruits.add("Guava");
       fruits.add("Pear");
           
       System.out.println("HashSet elements before sorting: "+fruits);
           
           
       // Method 1: Sorting HashSet using List interface
       List<String> fruitList = new ArrayList<String>(fruits);
       Collections.sort(fruitList);
           
       // Displaying list
       System.out.println("HashSet elements after sorting: "+fruitList);
           
       // Method 2: Sorting using TreeSet
       TreeSet<String> tset = new TreeSet<String>(fruits);
           
       System.out.println("HashSet elements after using TreeSet: "+tset);
   }

}

Output:

HashSet elements before sorting: [Pear, Guava, Apple, Banana, Orange]
HashSet elements after sorting: [Apple, Banana, Guava, Orange, Pear]
HashSet elements after using TreeSet: [Apple, Banana, Guava, Orange, Pear]

In method 1, we created a list and get the HashSet elements copied to it, then we have used the Collections.sort() method that sorts the elements of a list.
In method 2, we created a TreeSet and got the HashSet elements in TreeSet by providing the HashSet reference while creating TreeSet. As we are aware that TreeSet sorts its elements in ascending order, we ultimately got our HashSet elementns sorted out.
As you can see, we got the HashSet sorted out using above mentioned methods. The TreeSet method is preferred one because TreeSet is created for this purpose only.

Top Related Articles:

  1. LinkedHashMap in Java
  2. Java Scanner class with examples
  3. How to convert a HashSet to a TreeSet
  4. How to Convert an array to ArrayList in java
  5. Break statement in Java with example

Tags: Collections, Java-HashSet

About the Author

I have 15 years of experience in the IT industry, working with renowned multinational corporations. Additionally, I have dedicated over a decade to teaching, allowing me to refine my skills in delivering information in a simple and easily understandable manner.

– Chaitanya

Comments

  1. Anilkumar says

    September 18, 2015 at 11:53 AM

    Hello,
    Thank you for providing such nice stuff
    Your tutorials are very good and your way of explanation is quite good easy to understand..why don’t you provide another tutorials like Android

    Reply

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Java Tutorial

Java Introduction

  • Java Index
  • Java Introduction
  • History of Java
  • Features of Java
  • C++ vs Java
  • JDK vs JRE vs JVM
  • JVM - Java Virtual Machine
  • First Java Program
  • Variables
  • Data Types
  • Operators

Java Flow Control

  • Java If-else
  • Java Switch-Case
  • Java For loop
  • Java while loop
  • Java do-while loop
  • Continue statement
  • break statement

Java Arrays

  • Java Arrays

OOPs Concepts

  • OOPs Concepts
  • Constructor
  • Java String
  • Static keyword
  • Inheritance
  • Types of inheritance
  • Aggregation
  • Association
  • Super Keyword
  • Method overloading
  • Method overriding
  • Overloading vs Overriding
  • Polymorphism
  • Types of polymorphism
  • Static and dynamic binding
  • Abstract class and methods
  • Interface
  • Abstract class vs interface
  • Encapsulation
  • Packages
  • Access modifiers
  • Garbage Collection
  • Inner classes
  • Static import
  • Static constructor

Java Exception Handling

  • Exception handling
  • Java try-catch
  • Java throw
  • Java throws
  • Checked and Unchecked Exceptions
  • Jav try catch finally
  • Exception Examples
  • Exception Propagation

Collections Framework

  • Collections in Java
  • Java ArrayList
  • Java LinkedList
  • Java Vector
  • Java HashSet
  • Java LinkedHashSet
  • Java TreeSet
  • Java HashMap
  • Java TreeMap
  • Java LinkedHashMap
  • Java Queue
  • Java PriorityQueue
  • Java Deque
  • Comparable interface
  • Comparator interface
  • Collections Interview Questions

MORE ...

  • Java Scanner Class
  • Java 8 Features
  • Java 9 Features
  • Java Conversion
  • Java Date
  • Java Multithreading
  • Java I/O
  • Java Serialization
  • Java Regex
  • Java AWT
  • Java Swing
  • Java Enum
  • Java Annotations
  • Java main method
  • Java Interview Q

Copyright © 2012 – 2025 BeginnersBook . Privacy Policy . Sitemap