Java EE (Java Enterprise Edition) General Discussion

HI Friends,
anybody know the Answers of these questions.
I have an interview tomorrow.

1. Differentiate between interface and abstract class.

2. Define composition and aggregation.

3. What is the scope of protected modifier.

4. What is the signature of method definition.

5. How to create jdbc connection as unit application and as enterprise
connectivity.

6. How does servlet tracks sessions and what are the different methods to
do that.

7. What is the mandatory element of CMP EJB descriptor post EJB2.0.

8. What is the significance of JNDI in J2EE.

9. What is an exception and what are its types.

10 How do you instantiate a thread in java

Thanks
Sri