Method put

equalshashcode/SlowMap.java:12–20

(K key, V value)

  private List<K> keys = new ArrayList<>();
  private List<V> values = new ArrayList<>();
  @Override public V put(K key, V value) {
    V oldValue = get(key); // The old value or null
    if(!keys.contains(key)) {
      keys.add(key);
      values.add(value);
    } else
      values.set(keys.indexOf(key), value);
    return oldValue;
  }
  @Override
  public V get(Object key) { // key: type Object, not K
    if(!keys.contains(key))