Let's give you a crash course in Java EE web development.
Java EE web applications have two primary mechanisms for creating dynamic web pages:
JSP (Java Server Pages) --- HTML with embedded Java code. You use HTML to create the bulk of the page and Java for the dynamic parts.
Servlets --- Java objects that receive HTTP request and generate HTTP responses. These are useful for processing the data that is sent to the server when the user submits a form.
We will be using a mixture of JSP and servlets. JSP is good at displaying data to the user, and servlets are good at processing the data that the user sends to the web server (via forms).