The isEmpty() method of the 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 a boolean true if the map is empty or does not contain any mapping pairs else boolean false.
The below programs illustrate the working of the isEmpty() method:
Program 1:
Mapping String Values to Integer Keys.
// Java code to illustrate the isEmpty() method
import java.util.*;
// Driver Class
public class NavigableMap_Demo {
// Main Method
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.*;
// Driver Class
public class NavigableMap_Demo {
// Main Method
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