The typical log of events looks like:
-  Web server receives the request for dynamic content from the
     Web browser.
-  Request is reorganized and packaged in a specific format (one required
     by the communication protocol) and given to the connector module of 
     Web server.
-  Connector module sends the request to Application server and waits for
     the response.
-  Connector module receives response from the Application server and 
     passes it back to Web server.
-  Web server resturns the response to Web browser which originated the
     request
This is exactly how Tomcat behaves when it works in combo with the traditional
Apache Web server. Apache has a connector module
(
mod_jk) which forwards requests for servlets and JSP
to Tomcat. Tomcat runs them, and returns results to Apache, and Apache
returns them to Web Browser. Check my write-ups on:
https://server.ccl.net/cca/software/UNIX/apache.