Usage and example of Java HashMap isEmpty()

Java HashMap Methods

The Java HashMap isEmpty() method checks if the hash map is empty.

The syntax of isEmpty() method is:

hashmap.isEmpty()

isEmpty() parameters

isEmpty() method without any parameters.

The return value of isEmpty()

• If the hash map does not contain anyKey/ValueIf the mapping is present, return true

• If the hash map containsKey/ValueIf the mapping is not present, return false

Example: Check if the HashMap is empty

import java.util.HashMap;
class Main {
　　　　public static void main(String[] args) {
　　　　　　　　//Create HashMap
　　　　　　　　HashMap<String, Integer> languages = new HashMap<>();
　　　　　　　　System.out.println("The newly created HashMap: "　+　languages);
　　　　　　　　//Check if the HashMap contains any elements
　　　　　　　　boolean result = languages.isEmpty();　//　true
　　　　　　　　System.out.println("Is HashMap empty? ",　+　result);
　　　　　　　　//Insert some elements into the HashMap
　　　　　　　　languages.put("Python",　1);
　　　　　　　　languages.put("Java",　14);
　　　　　　　　System.out.println("Updated HashMap: ",　+　languages);
　　　　　　　　//Check if HashMap is Empty
　　　　　　　　result = languages.isEmpty();　　//　false
　　　　　　　　System.out.println("Is HashMap empty? ",　+　result);
　　　　}
}

Output Result

Newly created HashMap: {}
Is HashMap empty? true
Updated HashMap: {Java=14, Python =1}
Is HashMap empty? false

In the above example, we created a hash map named languages. Here, we used the isEmpty() method to check if the hash map contains any elements.

Initially, the newly created hash map does not contain any elements. Therefore, isEmpty() returns true. However, after adding some elements (Python,JavaAfter that, the method returns false.

Java HashMap Methods