HashMap in Java - Key-Value Pairs

HashMap

A HashMap stores items in "key/value" pairs, and you can access them by an index of another type (e.g. a String).

One object is used as a key (index) to another object (value).

import java.util.HashMap;
public class Main {
  public static void main(String[] args) {
    HashMap capitalCities = new HashMap();
    capitalCities.put("England", "London");
    capitalCities.put("Germany", "Berlin");
    capitalCities.put("Norway", "Oslo");
    capitalCities.put("USA", "Washington DC");
    System.out.println(capitalCities);
    
    // Access an item
    System.out.println(capitalCities.get("England"));
  }
}