For performance reasons, it makes sense to default to TCCL bus creation strategy on server side (that is, when running in-container). This means JAX-WS clients created on WildFly container will not use the bus linked to the current thread, but the one linked to the current thread context classloader. This effectively reduces the number of client busses by basically limiting it to the number of application deployments as well as prevents possible issues caused by thread pools (bus re-used by different applications...)
See https://docs.jboss.org/author/display/JBWS/Apache+CXF+integration#ApacheCXFintegration-BusselectionstrategiesforJAXWSclients for details on Bus creation strategies