Inheritance Across Packages

问题

Let's say we have package a and package b, both have many classes, all public.

Now class Cat from package a wants to extend class Animal from package b, is this inheritance legal?

回答1:

ASure, just import the parent class and extend it.

package a;

import b.Animal;

public class Cat extends Animal {

}

You can skip the import and use the fully qualified class name for Animal as well. But messier.

回答2:

Yes. Packages make grouping classes convenient, and non-public and non-private methods and fields are only visible to other members of the same package

来源：https://stackoverflow.com/questions/16312010/inheritance-across-packages