Ben Kirby Ben Kirby - 1 month ago 13
Java Question

ClassCastException when casting looked-up EJB view in AS7

I have am deploying 2 EARs onto JBoss AS 7.1.0.Alpha1-SNAPSHOT (post 7.0.1.Final version). Both deploy fine.

I have an EJB Singleton class packaged within a JAR, within one of the EARs:

@Startup
@Singleton
// one of @Local(Store.class), @Remote(Store.class), @LocalBean
@TransactionAttribute(TransactionAttributeType.NOT_SUPPORTED)
@Transactional(TransactionPropagation.SUPPORTS)
public class StoreFront implements Store {
...


public interface Store {
...


When it deploys, it says the EJB is bound to:

"java:app/store-core-2011.1.2-SNAPSHOT/StoreFront"
"java:app/store-core-2011.1.2-SNAPSHOT/StoreFront!uk.co.magus.jam.store.core.Store"
"java:module/StoreFront"
"java:module/StoreFront!uk.co.magus.jam.store.core.Store"
"java:global/store-ear-2011.1.2-SNAPSHOT/store-core-2011.1.2-SNAPSHOT/StoreFront!uk.co.magus.jam.store.core.Store"
"java:global/store-ear-2011.1.2-SNAPSHOT/store-core-2011.1.2-SNAPSHOT/StoreFront"


So far, so good. When I try to look it up via JNDI from a non-CDI, non-EJB class within a JAR within the OTHER deployed EAR, it can only be found on the JNDI names under 'global' - again, expected.

However, when I try to cast the resulting object to the actual interface class:

Object lookupObject = new InitialContext().lookup(jndiName);
Store store = (StoreFront)lookupObject;


I get the following exception:

11:17:52,402 ERROR [jam.core.link.LinkListener] (Thread-45) Exception when casting to Store after lookup with [java:global/store-ear-2011.1.2-SNAPSHOT/store-core-2011.1.2-SNAPSHOT/StoreFront]: java.lang.ClassCastException: jam.store.core.Store$$$view1 cannot be cast to jam.store.core.Store
at jam.core.link.LinkListener.getStore(LinkListener.java:108) [core-jar-2011.1.2-SNAPSHOT.jar:]
at jam.core.link.LinkListener.postLoad(LinkListener.java:27) [core-jar-2011.1.2-SNAPSHOT.jar:]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [:1.6.0_07]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) [:1.6.0_07]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) [:1.6.0_07]
at java.lang.reflect.Method.invoke(Method.java:597) [:1.6.0_07]
at org.hibernate.ejb.event.ListenerCallback.invoke(ListenerCallback.java:48)
at org.hibernate.ejb.event.EntityCallbackHandler.callback(EntityCallbackHandler.java:96)
at org.hibernate.ejb.event.EntityCallbackHandler.postLoad(EntityCallbackHandler.java:89)
at org.hibernate.ejb.event.EJB3PostLoadEventListener.onPostLoad(EJB3PostLoadEventListener.java:49)
at org.hibernate.engine.internal.TwoPhaseLoad.initializeEntity(TwoPhaseLoad.java:264)
at org.hibernate.loader.Loader.initializeEntitiesAndCollections(Loader.java:1012)
at org.hibernate.loader.Loader.doQuery(Loader.java:889)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:289)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:259)
at org.hibernate.loader.Loader.loadEntity(Loader.java:2058)
at org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:81)
at org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:71)
at org.hibernate.persister.entity.AbstractEntityPersister.load(AbstractEntityPersister.java:3686)
at org.hibernate.event.internal.DefaultLoadEventListener.loadFromDatasource(DefaultLoadEventListener.java:446)
at org.hibernate.event.internal.DefaultLoadEventListener.doLoad(DefaultLoadEventListener.java:427)
at org.hibernate.event.internal.DefaultLoadEventListener.load(DefaultLoadEventListener.java:204)
at org.hibernate.event.internal.DefaultLoadEventListener.proxyOrLoad(DefaultLoadEventListener.java:251)
at org.hibernate.event.internal.DefaultLoadEventListener.onLoad(DefaultLoadEventListener.java:148)
at org.hibernate.internal.SessionImpl.fireLoad(SessionImpl.java:947)
at org.hibernate.internal.SessionImpl.get(SessionImpl.java:863)
at org.hibernate.internal.SessionImpl.get(SessionImpl.java:856)
at org.hibernate.ejb.AbstractEntityManagerImpl.find(AbstractEntityManagerImpl.java:787)
at org.hibernate.ejb.AbstractEntityManagerImpl.find(AbstractEntityManagerImpl.java:762)
at org.jboss.as.jpa.container.AbstractEntityManager.find(AbstractEntityManager.java:220) [jboss-as-jpa-7.1.0.Alpha1-SNAPSHOT.jar:7.1.0.Alpha1-SNAPSHOT]
at jam.core.dao.GenericDAO.findById(GenericDAO.java:87) [core-jar-2011.1.2-SNAPSHOT.jar:]
at harvest.service.HarvesterDAOUtil.loadLink(HarvesterDAOUtil.java:251) [harvest-sar-2011.1.2-SNAPSHOT.jar:]
at harvest.service.1779224926$Proxy$_$$_WeldSubclass.loadLink(1779224926$Proxy$_$$_WeldSubclass.java) [harvest-sar-2011.1.2-SNAPSHOT.jar:]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [:1.6.0_07]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) [:1.6.0_07]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) [:1.6.0_07]
at java.lang.reflect.Method.invoke(Method.java:597) [:1.6.0_07]
at org.jboss.interceptor.proxy.SimpleInterceptionChain.invokeNextInterceptor(SimpleInterceptionChain.java:112) [jboss-interceptor-core-2.0.0.Alpha3.jar:2.0.0.Alpha3]
at org.jboss.interceptor.proxy.InterceptorInvocationContext.proceed(InterceptorInvocationContext.java:119) [jboss-interceptor-core-2.0.0.Alpha3.jar:2.0.0.Alpha3]
at org.jboss.seam.transaction.TransactionInterceptor$1.work(TransactionInterceptor.java:194) [seam-persistence-3.0.0.Final.jar:]
at org.jboss.seam.transaction.Work.workInTransaction(Work.java:54) [seam-persistence-3.0.0.Final.jar:]
at org.jboss.seam.transaction.TransactionInterceptor.aroundInvoke(TransactionInterceptor.java:188) [seam-persistence-3.0.0.Final.jar:]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [:1.6.0_07]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) [:1.6.0_07]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) [:1.6.0_07]
at java.lang.reflect.Method.invoke(Method.java:597) [:1.6.0_07]
at org.jboss.interceptor.proxy.InterceptorInvocation$InterceptorMethodInvocation.invoke(InterceptorInvocation.java:72) [jboss-interceptor-core-2.0.0.Alpha3.jar:2.0.0.Alpha3]
at org.jboss.interceptor.proxy.SimpleInterceptionChain.invokeNextInterceptor(SimpleInterceptionChain.java:82) [jboss-interceptor-core-2.0.0.Alpha3.jar:2.0.0.Alpha3]
at org.jboss.interceptor.proxy.InterceptorMethodHandler.executeInterception(InterceptorMethodHandler.java:133) [jboss-interceptor-core-2.0.0.Alpha3.jar:2.0.0.Alpha3]
at org.jboss.interceptor.proxy.InterceptorMethodHandler.invoke(InterceptorMethodHandler.java:112) [jboss-interceptor-core-2.0.0.Alpha3.jar:2.0.0.Alpha3]
at org.jboss.weld.bean.proxy.CombinedInterceptorAndDecoratorStackMethodHandler.invoke(CombinedInterceptorAndDecoratorStackMethodHandler.java:65) [weld-core-1.1.2.Final.jar:2011-07-26 15:02]
at harvest.service.1779224926$Proxy$_$$_WeldSubclass.loadLink(1779224926$Proxy$_$$_WeldSubclass.java) [harvest-sar-2011.1.2-SNAPSHOT.jar:]
at harvest.service.CombineHarvester.workOnLinkId(CombineHarvester.java:259) [harvest-sar-2011.1.2-SNAPSHOT.jar:]
at harvest.service.CombineHarvester.harvestCache(CombineHarvester.java:223) [harvest-sar-2011.1.2-SNAPSHOT.jar:]
at harvest.service.CombineHarvester.performHarvest(CombineHarvester.java:136) [harvest-sar-2011.1.2-SNAPSHOT.jar:]
at harvest.service.CombineHarvester.run(CombineHarvester.java:107) [harvest-sar-2011.1.2-SNAPSHOT.jar:]
at java.lang.Thread.run(Thread.java:619) [:1.6.0_07]


Whether the EJB is annotated with one from any of

@Local(Store.class)
@Remote(Store.class)
@LocalBean


makes no difference. As I understand it, the fact it's returning a proxy 'view' is normal. However, shouldn't I be able to cast that view to the interface? The combination of which global JNDI name I use and whether I cast to Store or StoreFront also appears to make no difference - unable to cast whatever the combination, even when the exception is like
jam.store.core.Store$$$view1 cannot be cast to jam.store.core.Store
, with matching (base) class names

Can anyone point out what I'm doing wrong?

Answer

This is a bug in AS7: https://issues.jboss.org/browse/AS7-1658

One possible workaround is not to cast the returned object, and then use it to fire methods via reflection. Well clunky though.