DO OR DIE
Clean my room.
Take out the trash.
Double RAM in server.
Take over the world by ruling a race of mindless robots that I control through my Tivo.
An abstract class is mostly potential. A regular class must implement all of the methods it declares. An abstract class can implement some of the methods it declares, and leave some for a subclass to implement.
The abstract class can be a useful thing. In this topic, we'll take a look at what they are, how to write them, how they behave, and when to use them.