How to sort TreeSet in descending order in Java?

To sort TreeSet in descending order, use the descendingSet() method in Java.

The descendingSet() method is used to return a reverse order view of the elements contained in this set.

At first, create a TreeSet −

TreeSet<Object> treeSet = new TreeSet<Object>();

Then add some elements −

treeSet.add(45);
treeSet.add(15);
treeSet.add(99);
treeSet.add(70);

Sort them indecreasing order −

TreeSet<Object> res = (TreeSet<Object>)treeSet.descendingSet();

Following is the code to sort TreeSet in descending order −

Example

 Live Demo

import java.util.TreeSet;
public class Main {
   public static void main(String[] args) {
      TreeSet<Object> treeSet = new TreeSet<Object>();
      treeSet.add(45);
      treeSet.add(15);
      treeSet.add(99);
      treeSet.add(70);
      treeSet.add(65);
      treeSet.add(30);
      treeSet.add(10);
      treeSet.add(60);
      treeSet.add(80);
      System.out.println("TreeSet\n" + treeSet);
      TreeSet<Object> res = (TreeSet<Object>)treeSet.descendingSet();
      System.out.println("TreeSet after sorting in descending order\n" + res);
   }
}

Output

TreeSet
[10, 15, 30, 45, 60, 65, 70, 80, 99]
TreeSet after sorting in descending order
[99, 80, 70, 65, 60, 45, 30, 15, 10]

AmitDiwan

Published on 20-Sep-2019 10:57:08