Servlet problems

[Kulkarni, Narayana]

I have a servlet called Test.
This servlet receives a Input file.
Passes on the contents of the Input file to various Class files for
processing.

Where DO I store the Test servlet.
Where Do I store the Related Classes?
If  I put eveything in examples/WEB-INF/classes or tomcat/classes will it
work? Is it violating the SandBox security model, where by a Class XX cannot
be called like
XX y = new XX() from within the Test servlet?

Your help is appreciated. Thanks