WeakHashMap values() Method in Java

Last Updated : 20 Jul, 2018

The java.util.WeakHashMap.values() method of HashMap class in Java is used to create a collection out of the values of the map. It basically returns a Collection view of the values in the Map.

Syntax:

Weak_Hash_Map.values()

Parameters: The method does not accept any parameters.

Return Value: The method is used to return a collection view containing all the values of the map.

Below programs are used to illustrate the working of java.util.WeakHashMap.values() Method:
Program 1:

// Java code to illustrate the values() method
import java.util.*;
  
public class Weak_Hash_Map_Demo {
    public static void main(String[] args)
    {
  
        // Creating an empty WeakHashMap
        Map<Integer, String> weak_hash = new 
                     WeakHashMap<Integer, String>();
  
        // Mapping string values to int keys
        weak_hash.put(10, "Geeks");
        weak_hash.put(15, "4");
        weak_hash.put(20, "Geeks");
        weak_hash.put(25, "Welcomes");
        weak_hash.put(30, "You");
  
        // Displaying the WeakHashMap
        System.out.println("Initial Mappings are: " + 
                                          weak_hash);
  
        // Using values() to get the set view of values
        System.out.println("The collection is: " + 
                                   weak_hash.values());
    }
}

Output:

Initial Mappings are: {30=You, 15=4, 10=Geeks, 25=Welcomes, 20=Geeks}
The collection is: [You, 4, Geeks, Welcomes, Geeks]

Program 2:

// Java code to illustrate the values() 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("Initial Mappings are: " + 
                                          weak_hash);
  
        // Using values() to get the set view of values
        System.out.println("The collection is: " + 
                                   weak_hash.values());
    }
}

Output:

Initial Mappings are: {Welcomes=25, 4=15, You=30, Geeks=20}
The collection is: [25, 15, 30, 20]

Note: The same operation can be performed with any type of Mappings with variation and combination of different data types.

Attention reader! Don’t stop learning now. Get hold of all the important Java Foundation and Collections concepts with the Fundamentals of Java and Java Collections Course at a student-friendly price and become industry ready. To complete your preparation from learning a language to DS Algo and many more, please refer Complete Interview Preparation Course.

My Personal Notes

Related Articles

WeakHashMap values() Method in Java