java.util.TreeMap.descendingKeySet() Method

Description

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.

Declaration

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

public NavigableSet<K> descendingKeySet()

Parameters

• NA

Return Value

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

Exception

• NA

Example

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]