Special Case in a Java Interface?

[justinm231]

A) I have two java interfaces: i1 and i2

B) Interface i1 contains int num = 10; ...while Interface i2 contains num = 20;

C) I then have an abstract class "TestClass" that implements i1 and i2.

D) If a TestClass method printOut() says: System.out.print(num); which num will be called since both are inherited?


Yes, I tested this in Java and it gives me an error: "num is ambiguous". I see clearly what is wrong with the inheritance and (I guess) I see how to fix it.

Is it correct to just say System.out.print(i1.num); ?

Can you please give me some discussion on this? I want to know how this should work in more complex situations!





Thank you, here is super simplified example code below, to demonstrate what I'm doing:

public interface i1 {
int num = 10;
public void delete();
}

public interface i2 {
int num = 20;
public void add();
}

public abstract TestClass implements i1,i2 {
System.out.print(i)
//or to correct --> System.out.print(i1.num); <--- ****** This part is what I am looking at ******

public void add(){
//Adds something non-applicable.
}
public void delete(){
//May delete that non-applicable something.
}
}

[Junky]

It depends upon what you are actually trying to do. It may simply be a matter of an incorrect design.

[justinm231]

Which would be an incorrect design? The ambiguity or inheritance structure? This is purely conceptual, I'm building this project as a learning aid to a tutorial I watched online.

[Junky]

There is no inheritance.

The design flaw could be due to many reasons. Why do you have 2 interfaces? Why do both interfaces have a variable with the same name? Why is you class implementing both interfaces? Should interface 2 extend interface 1?

[justinm231]

^^^Just the questions and concepts I was looking for.

That's perfect, thanks!

[Tolls]

It depends upon what you are actually trying to do. It may simply be a matter of an incorrect design.

I would argue sticking attributes into an interface is most definitely incorrect design...no ifs or buts.
Constants (static final), OK...but not attributes.