Java HashMap containsValue() Method

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Description

The Java HashMap containsValue(Object value) method is used to check if this map maps one or more keys to the specified value.

Declaration

Following is the declaration for java.util.HashMap.containsValue() method.

public boolean containsValue(Object value)

Parameters

value − This is the value whose presence in this map is to be tested.

Return Value

The method call returns 'true' if this map maps one or more keys to the specified value.

Exception

NA

Check a HashMap of Integer, Integer Pair for a Value Example

The following example shows the usage of Java HashMap containsValue() method to check if a value is present in a Map or not. We've created a Map object of Integer,Integer pair. Then few entries are added, map is printed and using containsValue() we're checking about two values in the map.

package com.tutorialspoint;

import java.util.HashMap;

public class HashMapDemo {
   public static void main(String args[]) {
      
      // create hash map
      HashMap<Integer,Integer> newmap = new HashMap<>();

      // populate hash map
      newmap.put(1, 1);
      newmap.put(2, 2);
      newmap.put(3, 3); 

      System.out.println("Initial map elements: " + newmap);
      System.out.println("Map contains 2 as value: " + newmap.containsValue(2));
      System.out.println("Map contains 4 as value: " + newmap.containsValue(4));
   }
}

Let us compile and run the above program, this will produce the following result.

Initial map elements: {1=1, 2=2, 3=3}
Map contains 2 as value: true
Map contains 4 as value: false

Check a HashMap of Integer, Integer Pair for a Value Example

The following example shows the usage of Java HashMap containsValue() method to check if a value is present in a Map or not. We've created a Map object of Integer,String. Then few entries are added, map is printed and using containsValue() we're checking about two values in the map.

package com.tutorialspoint;

import java.util.HashMap;

public class HashMapDemo {
   public static void main(String args[]) {
      
      // create hash map
      HashMap<Integer,String> newmap = new HashMap<>();

      // populate hash map
      newmap.put(1, "tutorials");
      newmap.put(2, "point");
      newmap.put(3, "is best"); 

      System.out.println("Initial map elements: " + newmap);
      System.out.println("Map contains tutorials as value: " + newmap.containsValue("tutorials"));
      System.out.println("Map contains java as value: " + newmap.containsValue("java"));
   }
}

Let us compile and run the above program, this will produce the following result.

Initial map elements: {1=tutorials, 2=point, 3=is best}
Map contains tutorials as value: true
Map contains java as value: false

Check a HashMap of Integer, Student Pair for a Key Example

The following example shows the usage of Java HashMap containsValue() method to check if a value is present in a Map or not. We've created a Map object of Integer,Student. Then few entries are added, map is printed and using containsValue() we're checking about two values in the map.

package com.tutorialspoint;

import java.util.HashMap;

public class HashMapDemo {
   public static void main(String args[]) {
      
      // create hash map
      HashMap<Integer,Student> newmap = new HashMap<>();

      // populate hash map
      newmap.put(1, new Student(1, "Julie"));
      newmap.put(2, new Student(2, "Robert"));
      newmap.put(3, new Student(3, "Adam"));

      System.out.println("Initial map elements: " + newmap);
      System.out.println("Map contains Robert as value: " + newmap.containsValue(new Student(2, "Robert")));
      System.out.println("Map contains Jene as value: " + newmap.containsValue(new Student(4, "Jene")));
   }
}
class Student {
   int rollNo;
   String name;

   Student(int rollNo, String name){
      this.rollNo = rollNo;
      this.name = name;
   }

   @Override
   public String toString() {
      return "[ " + this.rollNo + ", " + this.name + " ]";
   }
   @Override
   public boolean equals(Object obj) {
      if(obj == null) return false;
      Student s = (Student)obj;
      return this.rollNo == s.rollNo && this.name.equalsIgnoreCase(s.name);
   }
}

Let us compile and run the above program, this will produce the following result.

Initial map elements: {1=[ 1, Julie ], 2=[ 2, Robert ], 3=[ 3, Adam ]}
Map contains Robert as value: true
Map contains Jene as value: false