Enthuware

Explanation says :
The getValue(int i) method of class A in option c, is different than the method defined in the interface because their parameters are different. So this class does not actually implement the method of the interface and so it is declared abstract.

I'm assuming that getValue(int i) is in class B for the third option.
My question is when an abstract class implements an Interface, can it not implement the method in the interface..
ie in this question would it have been wrong if the third option was
abstract class B implements I1
{    
String getValue() { return "something"; }
}

A class can be marked abstract even if it does not have any abstract method. If your code would be valid even if it implements all the methods of an interface.

HTH,
Paul.

Regarding this partial explanation in option c, "...So this class does not actually implement the method of the interface and so it is declared abstract."

I can't figure out why the class has to be declared abstract. Why couldn't it be a non-abstract class? The method in option c is not an abstract method so why make the class abstract?

Thanks.

If a class says that it implements an interface but doesn't actually define all the interface methods, then it has to be declared abstract.
HTH,
Paul.

is it worth pointing out that option A wouldn't be correct even if it implemented the interface - because of default access in the methods?

the same could be said for option C (class B) - getValue(int i) isn't just incorrect because of the arguments, again it's got default access.

obviously the answers are correct, just thought that it might be worth pointing out (if i'm correct that is!)

nick

Yes, that is a good point as well.

I see option C is not correct b/c of the parameter difference, but had that been the same and it truly implements `getValue`; isn't it also not correct b/c it does not implement `setValue`? Therefore it would still need to be abstract for that reason as well?

Option 3 is this: and is a correct option.

sorry, I typed that wrong. I meant to say Option 3 needs to be abstract (b/c it doesn't implement all methods from the interface), not that it is incorrect.

Is that correct?