IdentityHashMap isEmpty() Method in Java

The java.util.IdentityHashMap.isEmpty() method of IdentityHashMap class 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:

Identity_Hash_Map.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 java.util.IdentityHashMap.isEmpty() method:

Program 1:

Mapping String Values to Integer Keys.

Java

// Java code to illustrate the isEmpty() method
import java.util.*;

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

        // Creating an empty IdentityHashMap
        Map<String, Integer> identity_hash = new
                     IdentityHashMap<String, Integer>();

        // Mapping int values to string keys
        identity_hash.put("Geeks", 10);
        identity_hash.put("4", 15);
        identity_hash.put("Geeks", 20);
        identity_hash.put("Welcomes", 25);
        identity_hash.put("You", 30);

        // Displaying the IdentityHashMap
        System.out.println("The Mappings are: "+
                                      identity_hash);

        // Checking for the emptiness of Map
        System.out.println("Is the map empty? "+
                           identity_hash.isEmpty());
    }
}

Output

The Mappings are: {Geeks=20, Welcomes=25, You=30, 4=15}
Is the map empty? false

Program 2:

For an empty IdentityHashMap

Java

// Java code to illustrate the isEmpty() method
import java.util.*;

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

        // Creating an empty IdentityHashMap
        Map<String, Integer> identity_hash = new
                  IdentityHashMap<String, Integer>();

        // Displaying the IdentityHashMap
        System.out.println("The Mappings are: "+
                                      identity_hash);

        // Checking for the emptiness of Map
        System.out.println("Is the map empty? "+
                            identity_hash.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