Is the supertype metacharacter sentence in the textbook correct?

Question

Java

Hello!
Quote from the textbook (English and Russian version, Thinking in Java):

The argument apples is a List of some type that is the base type of Apple; thus you know that it is safe to add an Apple or a subtype of Apple.

The apples argument is a List container for some type that is Apple's base type; it follows that Apple and Apple-derived types can be safely included in a container.

public class SuperTypeWildcards {
  static void writeTo(List<? super Apple> apples) {
  apples.add(new Apple());
  apples.add(new Jonathan());
  // apples.add(new Fruit()); // Error
}

I can't find the logic here. If apples is a List container for some type that is Apple 's base type, then why can't you add Fruit to the container, but you can add, for example, Jonathan , which is NOT Apple 's base type , but derived from it?

Answer 1

Read this link and this

Answer 2

The apples argument is a List container for some type whose base is Apple; it follows that Apple and Apple-derived types can be safely included in a container.