I'm not sure what you're getting at.
In the Petclinic web.xml is a declaration of a
servlet, org.springframework.web.context.ContextLoaderServlet, that takes care of loading the Spring application context files. Alternatively, a listener of type org.springframework.web.context.ContextLoaderListener could have been declared that does the same thing. Either method has the same result; the beans declared in the xml files (which are the application configuration files) are instantiated and wired up. This works the same way in any servlet container.
kktec<br />SCJP, SCWCD, SCJD<br />"What we observe is not nature itself, but nature exposed to our method of questioning." - Werner Heisenberg