继承中的私有方法 [英] Private methods in Inheritance

问题描述

这是一个有趣的代码片段：

Here's an interesting code snippet:

public class Superclass {

    public static void main (String[] args){
        Superclass obj = new Subclass();
        obj.doSomething(); #prints "from Superclass"
    }

    private void doSomething(){System.out.println("from Superclass");}
}

class Subclass extends Superclass {

    private void doSomething(){System.out.println("from Subclass");}

}

我知道子类不会继承其父级的私有成员，但是这里obj设法调用一个它应该没有访问权限的方法。在编译时，obj的类型为Superclass，在运行时类型为Subclass。

I know that subclasses do not inherit the private members of its parent, but here obj manages to call a method to which it should have no access. At compile time obj is of type Superclass, at runtime of type Subclass.

这可能与doSomething（）的调用发生在驱动程序类中的事实有关，而驱动程序类恰好是它自己的类（以及它的原因）可以在第一时间调用doSomething（）。

This probably has something to do with the fact that the call to doSomething() is taking place inside the driver class, which happens to be its own class (and why it's possible to invoke doSomething() in the first place).

所以问题归结为，obj如何访问其父级的私有成员？

So the question boils down to, how does obj have access to a private member of its parent?

推荐答案

你自己回答了。由于私有方法不是继承的，超类引用会调用自己的私有方法。

You answered it yourself. As the private methods are not inherited, a superclass reference calls its own private method.

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