Java – Get size of HashMap example

In this example we are gonna see how to get the size of HashMap using size() method of HashMap class. Method definition and description are as follows:

public int size(): Returns the number of key-value mappings in this map.

import java.util.HashMap;

public class SizeExample {
 
 public static void main(String[] args) {
 
    // Creating a HashMap of int keys and String values
    HashMap<Integer, String> hashmap = new HashMap<Integer, String>();
 
    // Adding Key and Value pairs to HashMap
    hashmap.put(11,"Value1");
    hashmap.put(22,"Value2");
    hashmap.put(33,"Value3");
    hashmap.put(44,"Value4");
    hashmap.put(55,"Value5");
 
    // int size() method returns the number of key value pairs 
    System.out.println("Size of HashMap : " + hashmap.size());
 }
}

Output:

Size of HashMap : 5

Since we have 5 key-value pairs in HashMap, the size() method returned integer number 5. Also, in the above example we have taken Integer keys and String values, however if you want to have String key and String value then you can change the generics like this:
HashMap<String, String> hashmap = new HashMap<String, String>();

Remember to add the pairs like this, If you have String keys and values.
hashmap.put("11", "Value1");