Interview Questions when 5 or 6 years of Java/J2EE experience

Gemstone
1. How would you implement your own Thread Pool.
2. What is NIO
3. Best way to read data from socket using traditional I/O
4. Beat way to read file.
5. How to read characters from InputStream.
6. How Serialization works
7. Synchronization
8. how to implement counter in servlet.
9. how hashtable is thread safe.
10. CharSet, Enocder, Decoder
11. AtomicInteger, volatile, transient.
12. JTA, XA, how XA works, two phase commit.
13. Role of transaction manager in XA transaction.
14. XADataSource, and closing XADataSource.
15. UserTransaction
16. JCA Architecture