coming to the point, It is better practice to make a jsp file name as start with small case; example : performLogin , so container like tomcat generate java class[servlet] name as like jsp file name; example : performLogin_jsp . is it not voilating the convention rule that java class name should start with capital letter.
The naming convention is just a convention, not a must. Although I would never think of writing a class starting with a lowercase letter. But as far as JSPs are concerned, this happens behind the scenes. All you see is JSPs, not the translated servlet. So, who cares ?