How to sort HashSet in Java

To sort HashSet in Java, you can use another class, which is TreeSet.

Following is the code to sort HashSet in Java −

Example

 Live Demo

import java.util.*; public class Main {    public static void main(String args[]) {       Set<String> hashSet = new HashSet<String>();       hashSet.add("green");       hashSet.add("blue");       hashSet.add("red");       hashSet.add("cyan");       hashSet.add("orange");       hashSet.add("green");       System.out.println("HashSet elements\n"+ hashSet);       Set<String> treeSet = new TreeSet<String>(hashSet);       System.out.println("Sorted elements\n"+ treeSet);    } }

Output

HashSet elements [red, orange, green, blue, cyan] Sorted elements [blue, cyan, green, orange, red]

Let us see another example wherein we will sort the HashSet in descending order using Collections.sort() method with reverseOrder() method −

Example

 Live Demo

import java.util.*; public class Main {    public static void main(String args[]) {       Set<String> hashSet = new HashSet<String>();       hashSet.add("yellow");       hashSet.add("green");       hashSet.add("blue");       hashSet.add("cyan");       hashSet.add("orange");       hashSet.add("green");       System.out.println("HashSet elements\n"+ hashSet);       List<String> myList = new ArrayList<String>(hashSet);       Collections.sort(myList,Collections.reverseOrder());       System.out.println("Sorted (descending order)\n"+ myList);    } }

Output

HashSet elements [orange, green, blue, yellow, cyan] Sorted (descending order) [yellow, orange, green, cyan, blue]