Java HashMap isEmpty() Method

Last Updated : 16 Jan, 2025

The isEmpty() method in Java HashMap class is used to check whether the map contains any key-value mappings.

Example 1: Checking isEmpty() after adding entries to the map

Java

// Mapping integer value to string keys
import java.util.HashMap;

public class Geeks {
    public static void main(String[] args)
    {

        // Creating an empty HashMap
        HashMap<String, Integer> hm
            = new HashMap<String, Integer>();

        // Mapping int values to string keys
        hm.put("Java", 1);
        hm.put("Programming", 2);
        hm.put("Language", 3);

        // Displaying the HashMap
        System.out.println("The Mappings are: " + hm);

        // Checking for the emptiness of Map
        System.out.println("Is the map empty? "
                           + hm.isEmpty());
    }
}

Output

The Mappings are: {Java=1, Language=3, Programming=2}
Is the map empty? false

Syntax of isEmpty() Method

public boolean isEmpty()

Return Type:

It returns true, if the map contains no key-value mapping.
It returns false, if the map has one or more key-value mapping.

Example 2: Check isEmpty() Before and After Adding Entries

Java

// Mapping String value to integer keys
import java.util.HashMap;

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

        // Display the HashMap
        System.out.println("HashMap contents: " 
                           + map);

        // Check if the map is empty
        System.out.println("Is the map empty? " 
                           + map.isEmpty());

        // Add key-value pairs
        map.put(1, "Java");
        map.put(2, "Programming");
        map.put(3, "Language");

        // Display the updated HashMap
        System.out.println("Updated HashMap contents: " 
                           + map);

        // Check if the map is empty again
        System.out.println("Is the map empty? " 
                           + map.isEmpty());
    }
}

Output

HashMap contents: {}
Is the map empty? true
Updated HashMap contents: {1=Java, 2=Programming, 3=Language}
Is the map empty? false

Example 3: Check isEmpty() on an Empty HashMap

Java

// Java program to demonstrate the working of isEmpty()
import java.util.HashMap;

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

        // Displaying the HashMap
        System.out.println("The Mappings are: " + hm);

        // Checking for the emptiness of Map
        System.out.println("Is the map empty? "
                           + hm.isEmpty());
    }
}

Output

The Mappings are: {}
Is the map empty? true

ConcurrentHashMap isEmpty() Method in Java

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