Originally posted by Anupama D S: Is it legal(not in terms of syntax) to define inner class inside abstract class does it comes under any design pattern?
If "not in terms of syntax", then what?
Anyway, the answer is yes, it is legal to have an inner class inside an abstract class.
Further, as well as being legal, it is also sometimes a reasonable thing to do. After all, an abstract class contains (partial) implementation code, and that implementation will sometimes be best achieved with the help of an inner class.
Betty Rubble? Well, I would go with Betty... but I'd be thinking of Wilma.