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() methodimport 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() methodimport 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