I found that most of them read HFSJ. BUT AJAX, JPA and JDBC is not covered in that book if I am not wrong. So please suggest me a book/material for that.
I don't remember seeing people here at javaranch mentioning questions about those subjects. Just check the Servlet specs on these topics.
The Servlet specs are very important (if you go for the EE6 exam) as is describes the topics that are new.
Regards,
Frits