Java Utility Library

Java TreeSet - descendingSet() Method

The java.util.TreeSet.descendingSet() method returns a reverse order view of the elements contained in this set. The descending set is backed by this set, so changes to the set are reflected in the descending set, and vice-versa.

Syntax

public NavigableSet<E> descendingSet()

Here, E is the type of element maintained by the container.

Parameters

No parameter is required.

Return Value

Returns a reverse order view of this set.

Exception

Example:

In the example below, the java.util.TreeSet.descendingSet() method returns a reverse order view of the given treeset.

import java.util.*;

public class MyClass {
  public static void main(String[] args) {
    //creating treesets
    TreeSet<Integer> MySet = new TreeSet<Integer>();
    TreeSet<Integer> Reverse_MySet = new TreeSet<Integer>();

    //populating the set
    MySet.add(40);
    MySet.add(20);
    MySet.add(10);
    MySet.add(30);

    //printing MySet
    System.out.println("MySet contains: " + MySet); 

    //creating reverse set
    Reverse_MySet = (TreeSet<Integer>)MySet.descendingSet();

    //printing Reverse_MySet
    System.out.println("Reverse_MySet contains: " + Reverse_MySet); 
  }
}

The output of the above code will be:

MySet contains: [10, 20, 30, 40]
Reverse_MySet contains: [40, 30, 20, 10]

❮ Java.util - TreeSet