Abstract classes VS Interface. Where have you used Abstract Class, 2 interface with same method then derived class will call, Can we have static constructors for class, why do u use, What is multi threading and what are complexities involved with it, What are generics and where have you used them, Session and application states in real life, Have you used WCF and which binding did you use, What are Generics , How do you use validations in forms (client, server), have you used Designing patterns, Explain abstract factory , Tables vs views, Can we make changes databse using views,