Map containsValue() method in Java with Examples

The java.util.Map.containsValue() method is used to check whether a particular value is being mapped by a single or more than one key in the Map. It takes the value as a parameter and returns True if that value is mapped by any of the key in the map.

Syntax:

boolean containsValue(Object Value)

Parameters: The method takes just one parameter Value of Object type and refers to the value whose mapping is supposed to be checked by any key inside the map.

Return Value: The method returns boolean true if the mapping of the value is detected else false.

Below programs illustrate the java.util.Map.containsValue() method:

Program 1: Mapping String Values to Integer Keys.

// Java code to illustrate the containsValue() method

import java.util.*;

public class Map_Demo {
    public static void main(String[] args)
    {
        // Creating an empty Map
        Map<Integer, String> map = new HashMap<Integer, String>();

        // Mapping string values to int keys
        map.put(10, "Geeks");
        map.put(15, "4");
        map.put(20, "Geeks");
        map.put(25, "Welcomes");
        map.put(30, "You");

        // Displaying the Map
        System.out.println("Initial Mappings are: " + map);

        // Checking for the Value 'Geeks'
        System.out.println("Is the value 'Geeks' present? " + map.containsValue("Geeks"));

        // Checking for the Value 'World'
        System.out.println("Is the value 'World' present? " + map.containsValue("World"));
    }
}

Output:

Initial Mappings are: {20=Geeks, 25=Welcomes, 10=Geeks, 30=You, 15=4}
Is the value 'Geeks' present? true
Is the value 'World' present? false

Program 2: Mapping Integer Values to String Keys.

// Java code to illustrate the containsValue() method

import java.util.*;

public class Map_Demo {
    public static void main(String[] args)
    {
        // Creating an empty Map
        Map<String, Integer> map = new HashMap<String, Integer>();

        // Mapping int values to string keys
        map.put("Geeks", 10);
        map.put("4", 15);
        map.put("Geeks", 20);
        map.put("Welcomes", 25);
        map.put("You", 30);

        // Displaying the Map
        System.out.println("Initial Mappings are: " + map);

        // Checking for the Value '10'
        System.out.println("Is the value '10' present? " + map.containsValue(10));

        // Checking for the Value '30'
        System.out.println("Is the value '30' present? " + map.containsValue(30));

        // Checking for the Value '40'
        System.out.println("Is the value '40' present? " + map.containsValue(40));
    }
}

Output:

Initial Mappings are: {4=15, Geeks=20, You=30, Welcomes=25}
Is the value '10' present? false
Is the value '30' present? true
Is the value '40' present? false

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

Reference: https://docs.oracle.com/javase/7/docs/api/java/util/Map.html#containsValue(java.lang.Object)