There are quite some differeces that i can find out ..
Let say if the request type is of ServletRequest then we can not get some of the container generated objects like HttpSession and may not be able to get the headers etc.
I tried to see the generated Servlet via netbeans for one my jsps and i could not see this particular request or response implicit object declared in the servlet....
When you look at the API for that class, what does it say it will pass to your servlet's doGet or doPost methods?
Doesn't that tell you what you will have to work with?
I think, though, the others were trying to get you to think about the broad differences between the ServletRequest and HttpServletRequest types. If you had to hazard a guess, what would be the number one biggest difference?
Hint: Don't think too hard about it. It's looking at you right in the face