Well, I think the lack of a definition for what is meant by abstract or abstraction is critical. For example there is some discussion of an abstract base class

Well, I think the lack of a definition for what is meant by abstract or abstraction is critical. For example there is some discussion of an abstract base class but the article keeps missing that in Object Oriented Programming the term abstract class exists. It describes an 'incomplete' class which cannot be used to instantiate objects but can be used to hold common behavior. http://www.javacoffeebreak.com/faq/faq0084.html http://www.javacoffeebreak.com/faq/faq0084.html