Check whether a NavigableMap empty or not in Java

The isEmpty() method is used in Java to check whether a NavigableMap is empty or not.

First, create a NavigableMap and add elements to it −

NavigableMap<Integer, String> n = new TreeMap<Integer, String>(); n.put(5, "Tom"); n.put(9, "John"); n.put(14, "Jamie"); n.put(1, "Tim"); n.put(4, "Jackie"); n.put(15, "Kurt"); n.put(19, "Tiger"); n.put(24, "Jacob");

Now, check whether the Map is empty or not −

System.out.println("Map is empty? " + n.isEmpty());

The following is an example to implement isEmpty() method and check whether the Map is empty −

Example

 Live Demo

import java.util.*; public class Demo {    public static void main(String[] args) {       NavigableMap<Integer, String> n = new TreeMap<Integer, String>();       n.put(5, "Tom");       n.put(9, "John");       n.put(14, "Jamie");       n.put(1, "Tim");       n.put(4, "Jackie");       n.put(15, "Kurt");       n.put(19, "Tiger");       n.put(24, "Jacob");       System.out.println("NavigableMap elements = "+n);       System.out.println("Size = "+n.size());       System.out.println("Map is empty? " + n.isEmpty());       // remove all elements       n.clear();       System.out.println("\nUpdated NavigableMap elements = "+n);       System.out.println("Size = "+n.size());       System.out.println("Map is empty? " + n.isEmpty());    } }

Output

NavigableMap elements = {1=Tim, 4=Jackie, 5=Tom, 9=John, 14=Jamie, 15=Kurt, 19=Tiger, 24=Jacob} Size = 8 Map is empty? false Updated NavigableMap elements = {} Size = 0 Map is empty? True