Hi, The following workaround has been checked in for EclipseLink M8 to work with JBoss 4.2.2 GA. Container managed entities should predeploy/deploy and register now with/without static weaving. When the UCL3 classLoader no longer causes a NPE (See JIRA http://jira.jboss.com/jira/browse/EJBTHREE-572 ) we will reenable dynamic weaving on EAR predeploy(). http://bugs.eclipse.org/229634 Workaround: --------------------------------- EclipseLink will use the non-temporary classLoader instead of the one from getNewTempClassLoader() obtained from the JBoss PersistenceUnitInfo that throws a NPE on loadClass() or Class.forName(). We require that JBoss implementers statically weave container managed entities and reference JBoss as the target-server in persistence.xml. Deployment Changes: 1) If weaving is required then static weave the entities before EAR packaging using either the command-line weaver or the weaving ant task. 2) All persistence units deployed to the JBoss container must contain the following property in persistence.xml or container managed entities will predeploy but fail to be managed at runtime. JBoss AS 4.2.2 GA debugging: ---------------------------------------------------------- I debugged the UCL3 NullPointerException into the JBoss AS 4.2.2 GA source into the following segment of code. In the following function the classloader parent tree is searched all the way to the root. no clazz is returned and in the finally clause the last log.trace causes a RuntimeException on a NPE. Curious though that the line number in Logger.trace() does not correspond to the JDK 1.5 src. package org.jboss.mx.loading public abstract class RepositoryClassLoader extends URLClassLoader public Class loadClass(String name, boolean resolve) throws ClassNotFoundException ... finally ... --->NPE log.trace("loadClass " + this + " name=" + name + " not found"); } } } Thread [main] (Suspended) UnifiedClassLoader3(RepositoryClassLoader).loadClass(String, boolean) line: 425 UnifiedClassLoader3(ClassLoader).loadClass(String) line: 251 UnifiedClassLoader3(ClassLoader).loadClassInternal(String) line: 319 Class.forName0(String, boolean, ClassLoader) line: not available [native method] Class.forName(String, boolean, ClassLoader) line: 242 PrivilegedAccessHelper.getClassForName(String, boolean, ClassLoader) line: 85 XMLEntityMappings.getClassForName(String, ClassLoader) line: 120 XMLEntityMappings.getClassForName(String) line: 157 XMLEntityMappings.initPersistenceUnitClasses() line: 389 MetadataProcessor.initPersistenceUnitClasses() line: 188 MetadataProcessor.processEntityMappings() line: 298 Results: -------- 15:41:43,772 INFO [STDOUT] [EPS Warning]: 2008.05.02 15:41:43.755--Thread(Thread[main,5,jboss])--The temporary classLoader for PersistenceLoadProcessor [helloworld] is not available. Switching classLoader to [org.jboss.mx.loading.UnifiedClassLoader3@18b995c{ url=file:/C:/opt/jboss422/server/default/tmp/deploy/tmp13465jsfejb3.ear ,addedOrder=45}]. Weaving has been disabled for this session. EclipseLink may be unable to get a spec mandated temporary class loader from the server, you may be able to use static weaving as an optional workaround. 15:41:44,221 INFO [JmxKernelAbstraction] installing MBean: jboss.j2ee:ear=jsfejb3.ear,jar=app.jar,name=TodoDao,service=EJB3 with dependencies: 15:41:44,221 INFO [JmxKernelAbstraction] persistence.units:ear=jsfejb3.ear,jar=app.jar,unitName=helloworld 15:41:44,359 INFO [EJBContainer] STARTED EJB: TodoDao ejbName: TodoDao 15:42:45,344 INFO [STDOUT] [EPS Finer]: 2008.05.02 15:42:45.343--UnitOfWork(20862427)--Thread(Thread[http-127.0.0.1-8080-1,5,jboss])--TX binding to tx mgr, status=STATUS_ACTIVE 15:42:45,344 INFO [STDOUT] [EPS Finest]: 2008.05.02 15:42:45.344--UnitOfWork(20862427)--Thread(Thread[http-127.0.0.1-8080-1,5,jboss])--Execute query DoesExistQuery() 15:42:45,350 INFO [STDOUT] [EPS Finest]: 2008.05.02 15:42:45.350--UnitOfWork(20862427)--Thread(Thread[http-127.0.0.1-8080-1,5,jboss])--PERSIST operation called on: Todo@15914f3. thank you /michael View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4148555#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...