That's a good question class.  And frankly, I'm glad you asked...

1. The JSP engine sends the request object to whatever server-side component (JavaBeans component, servlet,...) the JSP file specifies.

2. The component handles the request, possibly retrieving data from a database or other data store, and passes a response object back to the JSP engine.

3. The JSP engine passes the response object to the JSP page, where its data is formatted according the page's HTML design.

4. The JSP engine and Web server then send the revised JSP page back to the client, where the user can view the results in the Web browser.