Overriding return type in extended interface - Bad idea?

Question

In Java, you can do the following :

public interface IEngine{}
public interface ICoolEngine extends IEngine{}

public interface Car
{
   IEngine getEngine();         


        

Answer 1

What you're doing is completely OK.

I'd prefer to put it this way:

public interface IEngine { }
public interface ICoolEngine extends IEngine { }

public interface ICar {
   T getEngine();
}

public interface ICoolCar extends ICar { }

I used generics because as you used an annotation I guessed you're working on Java 5+