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Java HashMap size()

The Java HashMap size() method returns the number of key/value mappings present in the hashmap.

The syntax of the size() method is:

hashmap.size()

Here, hashmap is an object of the HashMap class.


size() Parameters

The size() method does not take any parameters.


size() Return Value

  • returns the number of key/value mappings present in the hashmap

Example: Java HashMap size()

import java.util.HashMap;

class Main {
    public static void main(String[] args) {
        // create an HashMap
        HashMap<String, String> countries = new HashMap<>();

        // insert keys/values to the HashMap
        countries.put("USA", "Washington");
        countries.put("UK", "London");
        countries.put("Canada", "Ottawa");
        System.out.println("HashMap: " + countries);

        // get the number of keys/values from HashMap
        int size = countries.size();
        System.out.println("Size of HashMap: " + size);
    }
}

Output

HashMap: {Canada=Ottawa, USA=Washington, UK=London}
Size of HashMap: 3

In the above example, we have created a hashmap named countries. Here, we have used the size() method to get the number of key/value mappings present in the hashmap.