in Difference between JAX-WS, Axis2 and CXF Daniel wrote
And for the most part, if you start with the in-jdk JAX-WS impl, you can drop in CXF at any time and it would still work.
I suppose that, deducting from your questions, you want to use Apache CXF. In reply to your questions:
For some particular application server, you need to specify some additional configuration. See Application Server Specific Configuration Guide.
Of course. The default behavior is most application server is load classes of the server first, then the classes in the module. Therefore Apache CXF may not work.
Yes. e.g. By default, Glassfish will use Metro for JAX-WS services so the classloader needs to be configured to allow CXF libraries to provide JAX-WS services.
If the classloader is configured properly, there will be no problems.
See also: