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IdentityHashMap isEmpty() Method in Java

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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 boolean true if the map is empty or does not contain any mapping pairs else boolean false. Below programs illustrates the working of java.util.IdentityHashMap.isEmpty() method: Program 1: Mapping String Values to Integer Keys.
// 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 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

Last Updated : 23 Jul, 2018
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