I've implemented a standard JAX-WS based webservice endpoint implementation bean as an EJB 3.0 stateless session bean. The endpoint implementation is packaged as an EAR and the package contains Spring framework 3.0 jars.

EAP has been configured to use JBossWS-CXF.
When I configure EARClassLoaderDeployer to use isolated classloaders (isolated=true) in:
server/$PROFILE/deployers/ear-deployer-jboss-beans.xml

I get the following error when invoking the webservice:

...
2011-12-21 22:37:20,537 ERROR [org.apache.catalina.core.ContainerBase.[jboss.web].[localhost].[/hello-service-ear-0.0.1-SNAPSHOT-hello-service-ejb-0.0.1-SNAPSHOT]] (http-127.0.0.1-8180-1) StandardWrapper.Throwable
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'HelloServiceEndpointBean': Invocation of init method failed; nested exception is java.lang.NoClassDefFoundError: org/mortbay/jetty/Connector
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1338)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:473)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory$1.run(AbstractAutowireCapableBeanFactory.java:409)
at java.security.AccessController.doPrivileged(Native Method)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:380)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:264)
...

Note that while the sample code bootstraps Spring using SpringBeanAutowiringInterceptor the issue can be reproduced even if the application doesn't bootstrap Spring and just by including the Spring jars in the deployment unit.