IdentityHashMap isEmpty() Method in Java

IdentityHashMap hashCode() 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("Beginner", 10); 
        identity_hash.put("4", 15); 
        identity_hash.put("Beginner", 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: {Beginner=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

Tags:

#Java-Collections #Java-Functions #java-IdentityHashMap #Java #Java #Java-Collections

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