CODEWITHSUNDEEP
javainheritance
Abhishek Saxena
Abhishek Saxena

Reputation: 292

Getting error "The inherited method in Abs.show() cannot hide the public abstract method in iface"

Getting error "The inherited method in Abs.show() cannot hide the public abstract method in iface" for the below written code.

package com.xprodev;
abstract class Abs {
    void show(){
        System.out.println("in show");
    }
    abstract public void print();

}
interface iface {
     void show();
     void print();
}

public class BasicAbs extends Abs implements iface {
    public static void main(String[] args){
        BasicAbs a = new BasicAbs();
        a.show();
        a.print();
    }

    @Override
    public void print() {
        System.out.println("in print");

    }
}

I can resolve the error by making show in Abs as public. But I have few questions

  1. Why the language support for this usage?
  2. What can be achieved if this is allowed?
  3. on calling a.print() only implementation of print will be called . Is that make sense to call this implementation is of method in Abs class or iface interface. Can we know that?

Upvotes: 1

Views: 653

Answers (1)

amit
amit

Reputation: 178481

Why the language support for this usage?

It's not - that's why you get an error

What can be achieved if this is allowed?

Recall that BasicAbs is-a Abs.
If you allow "auto conversion" of package protected to public in case of a conflict with interface, you damage encapsulation, you can basically create some interface with a method for every method you want to expose from the base class (which might be someone else's class), and that's not a good idea.

on calling a.print() only implementation of print will be called . Is that make sense to call this implementation is of method in Abs class or iface interface. Can we know that?

    Method m = BasicAbs.class.getMethod("print");
    System.out.println(m.getDeclaringClass());

Will yield:

class BasicAbs

Upvotes: 2

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