The java.util.HashMap.isEmpty() method of HashMap 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:
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.HashMap.isEmpty() method:
Program 1: Mapping String Values to Integer Keys.
// Java code to illustrate the isEmpty() methodimport java.util.*; public class Hash_Map_Demo { public static void main(String[] args) { // Creating an empty HashMap HashMap<String, Integer> hash_map = new HashMap<String, Integer>(); // Mapping int values to string keys hash_map.put("Geeks", 10); hash_map.put("4", 15); hash_map.put("Geeks", 20); hash_map.put("Welcomes", 25); hash_map.put("You", 30); // Displaying the HashMap System.out.println("The Mappings are: " + hash_map); // Checking for the emptiness of Map System.out.println("Is the map empty? " + hash_map.isEmpty()); }} |
Output:
The Mappings are: {4=15, Geeks=20, You=30, Welcomes=25}
Is the map empty? false
Program 2: For an empty HashMap
// Java code to illustrate the isEmpty() methodimport java.util.*; public class Hash_Map_Demo { public static void main(String[] args) { // Creating an empty HashMap HashMap<String, Integer> hash_map = new HashMap<String, Integer>(); // Displaying the HashMap System.out.println("The Mappings are: " + hash_map); // Checking for the emptiness of Map System.out.println("Is the map empty? " + hash_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.
