Java servlet JSP

Continuing the discussion from Greetings!:

Hi everyone

I have finished Java part1 and 70% of part 2. Step by step, i have created my Mortgage calculator with Mosh.

I have also created a simple Webpage using HTML and CSS. and I can also read HTML form data using JSP and Servlet. But I can not connect my Java Mortgage class to this HTML.

Can you help me?
It would be greate if I could find a comprehensive course on how to connect Java classes and methods to Servlet or JSP.

Best regards