WeakHashMap isEmpty() Method in Java with Examples

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

// Java code to illustrate the isEmpty() method
import 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

// Java code to illustrate the isEmpty() method
import 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

WeakHashMap isEmpty() Method in Java with Examples

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