java.util.TreeMap.descendingKeySet() Method



The descendingKeySet() method is used to return a reverse order NavigableSet view of the keys contained in this map. The set's iterator returns the keys in descending order. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa.


Following is the declaration for java.util.TreeMap.descendingKeySet() method.

public NavigableSet<K> descendingKeySet()


  • NA

Return Value

The method call returns a reverse order navigable set view of the keys in this map.


  • NA


The following example shows the usage of java.util.TreeMap.descendingKeySet() method.

package com.tutorialspoint;

import java.util.*;

public class TreeMapDemo {
   public static void main(String[] args) {
   // creating tree map 
   TreeMap<Integer, String> treemap = new TreeMap<Integer, String>();
   // populating tree map
   treemap.put(2, "two");
   treemap.put(1, "one");
   treemap.put(3, "three");
   treemap.put(6, "six");
   treemap.put(5, "five");
   // putting values in navigable set
   NavigableSet nset=treemap.descendingKeySet();
   System.out.println("Checking value");
   System.out.println("Navigable set values: "+nset);

Let us compile and run the above program, this will produce the following result.

Checking value
Navigable set values: [6, 5, 3, 2, 1]