JBOSS EAP 6.4.5 class loader issue

Hi, We have built CXF restful services with CXF 2.7.17 version. We are currently using jboss EAP 6.4.5, which comes with CXF 2.7.17 OOB jars. We are expecting the server libraries are available for war's classpath, which is not happening. Ran into java.lang.NoClassDefFoundError errors for CXF libraries. Should we have to change the class loaders to overcome this issue. How does the jboss parent-first classloader works.
Let me know if I can give more background on this.