在Java中继承是编译时还是运行时? [英] Is inheritance compile time or runtime in java

问题描述

有人告诉我继承是运行时，但是我想问一下，如果继承是运行时，那么当我们尝试通过子类对象访问父类数据成员时，编译器在编译时如何产生错误:

I was told that inheritance is runtime, but I want to ask that if inheritance is runtime then how does compiler generate error at compile time when we try to access parent class data member via child class object:

class PrivateData {
    private int x = 50;

    void show() {
        System.out.println(x);
    }
}

class ChildPrivateData extends PrivateData {

    public static void main(String s[]) {
        ChildPrivateData c1 = new ChildPrivateData();
        System.out.println(c1.x);
    }
}

推荐答案

继承绝对是在Java编译时定义的.我认为您将其与多态性混淆了，简而言之，它指出Java选择仅在运行时运行的重写方法.

Inheritance is most definitely defined at compile time in Java. I think you're confusing it with polymorphism, which, in a nutshell, states that Java chooses which overridden method to run only at runtime.

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