Using JSF and Struts

Question

I am a bit of a newbie in terms of UI applications on the JEE platform, so I apologize up front if this question seems silly. I was wondering if someone could comment on the approach below. Is this something that's possible or am I barking up the wrong tree?
We have a vendor application that is written using Struts. We want to add a section of our own pages to this application, but we would rather use a more strategic approach in our pages, so we would like to use JSF for those.
The original web.xml file in the vendor app uses a dtd of version 2.3 as shown below:
<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd">
When I use JSF, I use a DTD version of 2.5 as shown here:
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
The problem is that when I use version 2.3, the elements needed to support JSF are invalid. When I use 2.5, the elements needed to support struts are invalid.
Could someone comment in that, if you had this vendor app and you needed to add your own pages, is it not possible to use JSF in this scenario or if you can, what is the best approach to resolving this issue?
Thank you in advance

Answer 1

First make sure that your application server supports Servlet API 2.5. Whether the desired Servlet API version is supported or not solely depends on the application server implementation and version used. For example Tomcat 5.5 is a Servlet API 2.4 implementation which only supports the API versions up to with 2.4. If you want to use Servlet API 2.5, then you obviously need a Servlet API 2.5 implementation, for example Tomcat 6.0.
Consult the website and/or documentation of the application server in question.