W3School TIY Editor

import java.util.HashMap; public class Main { public static void main(String[] args) { HashMap<String, String> capitalCities = new HashMap<String, String>(); capitalCities.put("England", "London"); capitalCities.put("Germany", "Berlin"); capitalCities.put("China", "Beijing"); capitalCities.put("USA", "Washington DC"); System.out.println(capitalCities.size()); } }