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NavigableMap isEmpty() Method in Java
  • Last Updated : 31 Oct, 2018

The isEmpty() method of NavigableMap interface is used to check for the emptiness of the map. The method returns True if no key-value pair or mapping is present in the map else False.

Syntax:

NavigableMap.isEmpty()

Parameters: The method does not take any parameters.

Return Value: The method returns boolean true if the map is empty or does not contain any mapping pairs else boolean false.

Below programs illustrates the working of isEmpty() method:
Program 1: Mapping String Values to Integer Keys.






// Java code to illustrate the isEmpty() method
import java.util.*;
  
public class NavigableMap_Demo {
    public static void main(String[] args)
    {
  
        // Creating an empty NavigableMap
        NavigableMap<String, Integer> nav_map = new TreeMap<String, Integer>();
  
        // Mapping int values to string keys
        nav_map.put("Geeks", 10);
        nav_map.put("4", 15);
        nav_map.put("Geeks", 20);
        nav_map.put("Welcomes", 25);
        nav_map.put("You", 30);
  
        // Displaying the NavigableMap
        System.out.println("The Mappings are: " + nav_map);
  
        // Checking for the emptiness of Map
        System.out.println("Is the map empty? " + nav_map.isEmpty());
    }
}
Output:
The Mappings are: {4=15, Geeks=20, Welcomes=25, You=30}
Is the map empty? false

Program 2: For an empty IdentityHashMap




// Java code to illustrate the isEmpty() method
import java.util.*;
  
public class NavigableMap_Demo {
    public static void main(String[] args)
    {
  
        // Creating an empty NavigableMap
        NavigableMap<String, Integer> nav_map = new TreeMap<String, Integer>();
  
        // Displaying the NavigableMap
        System.out.println("The Mappings are: " + nav_map);
  
        // Checking for the emptiness of Map
        System.out.println("Is the map empty? " + nav_map.isEmpty());
    }
}
Output:
The Mappings are: {}
Is the map empty? true

Note: The same operation can be performed with any type of Mappings with variation and combination of different data types.

All methods of Java.util.IdentityHashMap Class

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