Java 保护访问不起作用

Question

在 java 中，存在三种访问级别:

• 公开 - 向世界开放
• 私有(private) - 只对类(class)开放
• protected - 仅对类及其子类开放(继承)。

那么为什么 java 编译器允许这种情况发生呢？

TestBlah.java:

public class TestBlah {

    public static void main(String[] args) {
        Blah a = new Blah("Blah");
        Bloo b = new Bloo("Bloo");
        System.out.println(a.getMessage());
        System.out.println(b.getMessage()); //Works
        System.out.println(a.testing);
        System.out.println(b.testing); //Works
    }
}

Blah.java:

public class Blah {
    protected String message;

    public Blah(String msg) {
        this.message = msg;
    }

    protected String getMessage(){
        return(this.message);
    }   
}

Bloo.java:

public class Bloo extends Blah {
    public Bloo(String testing) {
        super(testing);
    }
}

Answer 1

其实应该是:

Open only to the classes on the same package the class and its subclasses (inheritance)

这就是为什么