Without frameworks, it is probably OK if you already have a working web.xml. I used to just copy my working web.xml and modify it. Good luck if you want to create a working web.xml from scratch, though. The specification for a proper web.xml is a PDF with several 100 pages (last time I looked, a couple of years ago), and to parse it you basically need a scanner for XML specification files in your brain.
That is only for creating the working web.xml. Specifications for JSP and JSTL are several hundred pages on top of that.