Java私有方法覆盖 [英] Java private method override

问题描述

我遇到了这种情况。我们有一个类让我们说主要有私人方法打印。另一个类Main1扩展了Main类并重新定义了print方法。由于main1是Main1类的对象，我希望调用main1 print方法...

I came across this scenario. We have a class lets say Main having a private method print. There is another class Main1 which extends Main class and redefines the print method. Since main1 is an object of Main1 class, I expect main1 print method to get called...

public class Main {
    public static void main(String[] args) {
       Main main1 = new Main1();
       List<String> list = new ArrayList<String>();
       main1.print(list);
    }

    private void print(List<String> string) {
       System.out.println("main");
    }

}

class Main1 extends Main {
    public void print(List<String> string) {
       System.out.println("main1");
    }
}

在这种情况下，当我们运行程序时，它打印主要。它真的让我感到困惑，因为该方法是私有的，甚至不是Main1类的一部分。

In this case, when we run the program, it print "main". It really confuses me as that method is private and is not even part of Main1 class.

推荐答案

答案并不太难：

• main1 变量的类型是 Main （不 Main1 ）


• 所以你只能调用该类型的方法


• 唯一可能的方法是 print ，它接受 List< String> 主是私人


• 调用代码在类中主所以它可以调用该类中的私有方法

• the type of the main1 variable is Main (not Main1)
• so you can only call methods of that type
• the only possible method called print that accepts a List<String> on Main is the private one
• the calling code is inside the class Main so it can call a private method in that class

因此 Main。将调用print（List< String>）。

请注意，更改 main1的类型到 Main1 将导致其他 打印（List< String>）被调用的方法。

Note that changing the type of main1 to Main1 will result in the other print(List<String>) method being called.

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