how can access the age field of parent's parent in class C?

Question

I teach some students.
How I can access A class's attribute age?

class A {
    protected int age;
    public A(int age){
        this.age = age+2;
    }
}
class B extends A{
    protected int age;
    public B(int age){
        super(age);
        this.age = age+1;
    }
}
class C extends B{
    protected int age;
    public C(int age){
        super(age);
        this.age = age;
    }
    public void showInfo(){
//      System.out.println(A.this.age);
        System.out.println(super.age);
        System.out.println(this.age);
    }
}

By adding `protected int age;` to the subclasses I think you are shadowing the super variable — Scary Wombat, Jul 05 '17 at 01:47
@HovercraftFullOfEels I've seen a very similar sentence in an advertisement for an English teacher. — Dawood ibn Kareem, Jul 05 '17 at 01:53
Try to include `public void showInfo()` even in class B and in that you print `super.age` and then you call the function `super.showinfo()` in the overridden method in class C — Madhusudan chowdary, Jul 05 '17 at 01:54
@HovercraftFullOfEels better now? Doesn't make it into a good question, but it clears out that difficulty. — ItamarG3, Jul 05 '17 at 05:22

score 0 · Answer 1 · answered Jul 05 '17 at 01:51

0

It violates principles of object oriented design and is not possible in Java. There are some ugly workarounds, but if you're teaching students then it may be best to not even introduce this idea, or at least explain why it doesn't make sense.

This question is almost a duplicate if you really need a way of doing this: Why is super.super.method(); not allowed in Java?

answered Jul 05 '17 at 01:51

nickburris

11
4

thanks nickburris. yes i know you mentioned already. i just wondered whether it can be accessed or not. – user3866900 Jul 05 '17 at 01:54

score 0 · Answer 2 · answered Jul 05 '17 at 04:09

With Following code , you can achieve.

class A{
    protected int age;
    public A(int age){
        this.age = age+2;
    }

    public void showInfo()
    {
        System.out.println("A : " +  this.age);
    }
}
class B extends A{
    protected int age;
    public B(int age){
        super(age);
        this.age = age+1;
    }

    public void showInfo()
    {
        super.showInfo();
        System.out.println("B : " +  this.age);
    }
}
class C extends B{
    protected int age;
    public C(int age)
    {
        super(age);
        this.age = age;
    }
    public void showInfo()
    {
        super.showInfo();
        System.out.println("C : " +  this.age);
    }
}

how can access the age field of parent's parent in class C?

2 Answers2