This week's book giveaway is in the OCMJEA forum. We're giving away four copies of OCM Java EE 6 Enterprise Architect Exam Guide and have Paul Allen & Joseph Bambara 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.