While of course spring would not be needed in that case, the deployment unit classloader would not see the required cxf classes from cxf jars (as those need to be in the isolated classloader together with the spring jars because some classes in cxf jars references classes in spring jars).
This looks more complicated then, and it would be good to know the details.
e.g. we could add "the needed cxf classes that rely on spring" (crs) dynamically
* hopefully we can lookup @Endpoint annotation w/o crs
* if there is @Endpoint present in deployment, add crs to deployment's classpath
** if spring is already in deployment, only add (crs - spring)
Just thinking out loud ... :-)