What could make JAX-RS try to use some sort of sun class?

[Benson Margulies]

java.lang.RuntimeException: java.lang.RuntimeException:
java.lang.ClassNotFoundException:
com.sun.ws.rs.ext.RuntimeDelegateImpl
        at 
org.apache.cxf.jaxrs.client.JAXRSClientFactoryBean.createWebClient(JAXRSClientFactoryBean.java:217)


This is happening inside of a maven plugin, only with maven 2.2.1. Is
there some dependency I need to add?