Why FacesServlet cannot have a url-pattern of /*.?

Question

This is my web.xml :

<servlet-mapping>
    <servlet-name>Faces Servlet</servlet>
    <url-pattern>/*</url-pattern>
</servlet-mapping>

When I navigate to:

http://localhost:8080/LearningRoot/index.xhtml

I can see the page just fine, however when I navigate to:

http://localhost:8080/LearningRoot/

I get the error:

An Error Occurred:

The FacesServlet cannot have a url-pattern of /*. Please define a different url-pattern.

But why?

And this is my welcome file:

<welcome-file-list>
    <welcome-file>/index.xhtml</welcome-file>
</welcome-file-list>

Answer 1

Because that would mean Everything that ever hits that context-root will be handled by FacesServlet, a requirement that FacesServlet already knows it couldn't possibly fulfill (It obviously doesn't make sense).

To achieve the mapping you intend, use a .xhtml mapping on FaceServlet

<servlet-mapping>
  <servlet-name>Faces Servlet</servlet-name>
  <url-pattern>*.xhtml</url-pattern>
</servlet-mapping>