Why is guava's Cache.invalidate(Object key) method not generic?

Question

From the javadocs:

public interface Cache<K,V> extends Function<K,V> {
    //...
    void invalidate(Object key);
    //...
}

Why is this not rendered as a generic method:

    void invalidate(K key);

Is there a technical reason, a historical reason, or some other reason?

Answer 1

For the same reason that Map.remove takes an Object argument, which is explained here and here.

This reason is neither technical nor historical: it's just...an objectively sensible reason.