Pandian,
Paul has cleared your queries, apologies for the delay in reply. Was busy with my WCD certification preparation.
I hope you are learning Servlets and JSP (just like me
) and hence would suggest you to read HF Servlets and JSP (first six chapters).
It s pretty easy and straight forward and might take around 30 hours at the max.
If you are not able get HF Servlets and JSP, then try Core Servlets and JavaServer Pages by Marty Hall. First 9 chapters. Entire book is available as a free download.
http://volume2.coreservlets.com/
I felt most of queries would not have come in case you would read the chapters mentioned.
Good luck to you.