为什么一个类不能定义为受保护的? [英] Why can a class not be defined as protected?

问题描述

为什么我们不能将类定义为protected?

Why can we not define a class as protected?

我知道我们不能，但为什么呢?应该有一些具体的原因.

I know that we can't, but why? There should be some specific reason.

推荐答案

因为没有意义.

受保护的类成员(方法或变量)就像包私有(默认可见性)一样，除了它也可以从子类访问.
由于在 Java 中没有子包"或包继承"这样的概念，因此声明类受保护或包私有是一回事.

Protected class member (method or variable) is just like package-private (default visibility), except that it also can be accessed from subclasses.
Since there's no such concept as 'subpackage' or 'package-inheritance' in Java, declaring class protected or package-private would be the same thing.

不过，您可以将嵌套类和内部类声明为受保护的或私有的.

You can declare nested and inner classes as protected or private, though.

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