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How to check if a HashMap is empty or not?

By Chaitanya Singh | Filed Under: java

Description

Program to check if a HashMap is empty or not. We are using isEmpty() method of HashMap class to perform this check.

Program

import java.util.HashMap;
class HashMapIsEmptyExample{

  public static void main(String args[]) {
 
    // Create a HashMap
    HashMap<Integer, String> hmap = new HashMap<Integer, String>(); 
 
 
    // Checking whether HashMap is empty or not
    /* isEmpty() method signature and description -
     * public boolean isEmpty(): Returns true if this map 
     * contains no key-value mappings.
     */
    System.out.println("Is HashMap Empty? "+hmap.isEmpty());
 
    // Adding few elements
    hmap.put(11, "Jack");
    hmap.put(22, "Rock");
    hmap.put(33, "Rick");
    hmap.put(44, "Smith");
    hmap.put(55, "Will");
 
    // Checking again
    System.out.println("Is HashMap Empty? "+hmap.isEmpty());
  } 
}

Output:

Is HashMap Empty? true
Is HashMap Empty? false

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