Error is visible when uninstalling CMF for instance: currently a config file with a listener is not removed from the config folder, so the listener fails to register but error is confusing
2012-02-18 12:25:31,436 ERROR [org.nuxeo.common.xmap.XValueFactory] Cannot load class: java.lang.ClassNotFoundException: org.nuxeo.cm.event.MailInjectionList
ener
2012-02-18 12:25:31,437 ERROR [org.nuxeo.ecm.core.event.impl.EventServiceImpl] Failed to register event listener: CmMailInjectionListener
java.lang.IllegalArgumentException: Listener extension must define either a class or a script
at org.nuxeo.ecm.core.event.impl.EventListenerDescriptor.initListener(EventListenerDescriptor.java:139)
at org.nuxeo.ecm.core.event.impl.EventListenerList.add(EventListenerList.java:60)
at org.nuxeo.ecm.core.event.impl.EventServiceImpl.addEventListener(EventServiceImpl.java:121)
at org.nuxeo.ecm.core.event.EventServiceComponent.registerContribution(EventServiceComponent.java:56)