Java TreeMap.descendingMap() example

Java TreeMap.descendingMap() example

By technicalkeeda, Views 434, Date 21-Feb-2018

In this java tutorial, You will learn how to use descendingKeySet() method of TreeMap class.The descendingMap() method is used to return a reverse order view of the mappings contained in this map. The descending map is backed by this map, so changes to the map are reflected in the descending map, and vice-versa.

tags Java

Returns a reverse order view of the mappings contained in this map.

syntax

public NavigableMap<K,V> descendingMap()

Returns

a reverse order view of this map.

Java TreeMap descendingMap() example

  • Create TreeMap instance new TreeMap < Integer, String > ();
  • Add few elements in TreeMap e.g. students.put(1, "Pooja");
  • Print the TreeMap values.
  • students.descendingMap(); returns a reverse order view of the mappings contained in this map
  • Print descending map values.
package com.technicalkeeda;

import java.util.NavigableMap;
import java.util.TreeMap;

public class App {
    public static void main(String args[]) {

        TreeMap < Integer, String > students = new TreeMap < Integer, String > ();

        students.put(1, "Pooja");
        students.put(2, "Ajit");
        students.put(3, "Yashwant");
        students.put(4, "Aditi");

        System.out.println("TreeMap values :- " + students);

        NavigableMap reverseStudent = students.descendingMap();

        System.out.println("Values in reverse order:- " + reverseStudent);

    }
}

output

TreeMap values :- {1=Pooja, 2=Ajit, 3=Yashwant, 4=Aditi}
Values in reverse order:- {4=Aditi, 3=Yashwant, 2=Ajit, 1=Pooja}
Yashwant

Yashwant

Hi there! I am founder of technicalkeeda.com and programming enthusiast. My skills includes Java,J2EE, Spring Framework, Nodejs, PHP and lot more. If you have any idea that you would want me to develop? Lets connect: yashwantchavan[at][gmail.com]