Fred u r correct.
usualy u will have a JSP page call a servlet (instead of servlet calling a servlet).
but like bear said above, u dont have to.
u can put all your java code in the jsp page.
for convience sake, its is more likely to seperate real java code from the jsp page but hey thats just what i use and think
also, there is a also an added bonus of using jsp pages. u can add java beans to jsp pages with an ease. that way u can put your code (like connecting to a database) inside a bean and add that bean to the jsp page (instead of letting a servlet do that).