Map

A Map is a collection that maps keys to values. Maps that come with Java implement the java.util.Map interface.

interface Map<K, V> {
    V get(Object key);
    V put(K key, V value);
    // and more
}

HashMap is one implementation of Map you are likely to see and use.

import java.util.Map;
import java.util.HashMap;

class Main {
    void main() {
        Map<String, Integer> ages = new HashMap<>();
        ages.put("Andor", 26);
        ages.put("Bix", 27);
        ages.put("Luthen", 59);

        IO.println(ages);
    }
}

Just like ArrayList and List, all the useful capabilities of HashMap are available via the Map interface.