This week's book giveaway is in the Mac OS forum. We're giving away four copies of a choice of "Take Control of Upgrading to Yosemite" or "Take Control of Automating Your Mac" and have Joe Kissell on-line! See this thread for details.
1.The abstract class Dog can but do not need to implement astract makeASound method from his superclass Animal
2.The regular class Rottweiler must implements all abstract methods form his super class/classes (Animal class and Dog class).
Here, the concrete class Rottweiler does not need to implement makeASound(), as it was already implemented by its direct superclass Dog. But it is mandatory for Rottweiler class to implement command() method.