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