I have a small JavaEE5 sample app, which consists of a stateless bean, a web client project (servlet + jsp) and an app client app, all bundled to an EAR file. There are no annotations, just deployment descriptors. The app worked fine on AS5.

I copy it to the "standalone\deployed" folder of a JBoss pulled from GIT and built yesterday (2011-04-06). It fails with this error:

23:12:28,258 ERROR [org.jboss.msc.service.fail] (MSC service thread 1-3) MSC00001: Failed to start service jboss.deployment.unit."Stateless.ear"."StatelessWeb.war".INSTALL: org.jboss.msc.service.StartException in service jboss.deployment.unit."Stateless.ear"."StatelessWeb.war".INSTALL: Failed to process phase INSTALL of subdeployment "StatelessWeb.war" of deployment "Stateless.ear"
at org.jboss.as.server.deployment.DeploymentUnitPhaseService.start(DeploymentUnitPhaseService.java:108)
at org.jboss.msc.service.ServiceControllerImpl$StartTask.run(ServiceControllerImpl.java:1344)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) [:1.6.0_24]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) [:1.6.0_24]
at java.lang.Thread.run(Thread.java:662) [:1.6.0_24]
Caused by: java.lang.IllegalArgumentException: key is null
at org.jboss.msc.service.UnlockedReadHashMap.put(UnlockedReadHashMap.java:230)
at org.jboss.msc.service.ServiceContainerImpl.getOrCreateRegistration(ServiceContainerImpl.java:431)
at org.jboss.msc.service.ServiceContainerImpl.install(ServiceContainerImpl.java:499)
at org.jboss.msc.service.ServiceTargetImpl.install(ServiceTargetImpl.java:188)
at org.jboss.msc.service.ServiceControllerImpl$ChildServiceTarget.install(ServiceControllerImpl.java:1808)
at org.jboss.msc.service.ServiceTargetImpl.install(ServiceTargetImpl.java:188)
at org.jboss.msc.service.ServiceControllerImpl$ChildServiceTarget.install(ServiceControllerImpl.java:1808)
at org.jboss.msc.service.ServiceTargetImpl.install(ServiceTargetImpl.java:188)
at org.jboss.msc.service.ServiceControllerImpl$ChildServiceTarget.install(ServiceControllerImpl.java:1808)
at org.jboss.msc.service.ServiceTargetImpl.install(ServiceTargetImpl.java:188)
at org.jboss.msc.service.ServiceControllerImpl$ChildServiceTarget.install(ServiceControllerImpl.java:1808)
at org.jboss.msc.service.ServiceTargetImpl.install(ServiceTargetImpl.java:188)
at org.jboss.msc.service.ServiceControllerImpl$ChildServiceTarget.install(ServiceControllerImpl.java:1808)
at org.jboss.msc.service.ServiceTargetImpl.install(ServiceTargetImpl.java:188)
at org.jboss.msc.service.ServiceControllerImpl$ChildServiceTarget.install(ServiceControllerImpl.java:1808)
at org.jboss.msc.service.ServiceTargetImpl.install(ServiceTargetImpl.java:188)
at org.jboss.msc.service.ServiceControllerImpl$ChildServiceTarget.install(ServiceControllerImpl.java:1808)
at org.jboss.msc.service.ServiceTargetImpl.install(ServiceTargetImpl.java:188)
at org.jboss.msc.service.ServiceControllerImpl$ChildServiceTarget.install(ServiceControllerImpl.java:1808)
at org.jboss.msc.service.ServiceTargetImpl.install(ServiceTargetImpl.java:188)
at org.jboss.msc.service.ServiceControllerImpl$ChildServiceTarget.install(ServiceControllerImpl.java:1808)
at org.jboss.msc.service.ServiceTargetImpl.install(ServiceTargetImpl.java:188)
at org.jboss.msc.service.ServiceControllerImpl$ChildServiceTarget.install(ServiceControllerImpl.java:1808)
at org.jboss.msc.service.ServiceTargetImpl.install(ServiceTargetImpl.java:188)
at org.jboss.msc.service.ServiceControllerImpl$ChildServiceTarget.install(ServiceControllerImpl.java:1808)
at org.jboss.msc.service.ServiceTargetImpl.install(ServiceTargetImpl.java:188)
at org.jboss.msc.service.ServiceControllerImpl$ChildServiceTarget.install(ServiceControllerImpl.java:1808)
at org.jboss.msc.service.ServiceBuilderImpl.install(ServiceBuilderImpl.java:310)
at org.jboss.as.ee.component.ModuleJndiBindingProcessor.addJndiBinding(ModuleJndiBindingProcessor.java:83)
at org.jboss.as.ee.component.ModuleJndiBindingProcessor.deploy(ModuleJndiBindingProcessor.java:51)
at org.jboss.as.server.deployment.DeploymentUnitPhaseService.start(DeploymentUnitPhaseService.java:102)
... 4 more

The sample can be found here: http://www.cs.hs-rm.de/~knauf/KomponentenArchitekturen2008/stateless/StatelessNoAnnotation.ear
(rename EAR file to "Stateless.ear" before deploying)

The same sample, which uses annotations instead of deployment descriptors, deploys without errors (http://www.cs.hs-rm.de/~knauf/KomponentenArchitekturen2008/stateless/Stateless.ear).