Hibernate version:2.1.6

We got a strange problem during flushing a session. The problem is a NullPointerException throwed by Hibernate. We try to locate it and we have found that the original problem comes from the next method:



When obtains the "entry" reference it comes null and then the story is known... NullPointerExcception

Any idea??
Thanks...

Of course we can't help you unless you show the full stack trace, and your code.


http://www.hibernate.org/ForumMailingli ... AskForHelp

What stack trace?... there is nothing there.. just the nullpointerexception with a null message of course... nothing else..

About the code... i'm trying to get it together but it will take some time... but what it's doing is loading a object "A", putting another object "B" inside one of the collections of "A", saveOrUpdate() "A", and try to flush... then crash..

of course there is a stacktrace. you own code swallows it

You're right, but the fact is that the hibernate method we post don't consider the possibility that the reference could come null using the variable assuming that it could never come null. What we are trying to understand is that if the problem is coused by a bug in the framework or by a result of wrong use of it...

The sequence of our application before the crash is like we told you on the precedent messages but we try to exlpain you again:

1-load an object (in this process we obtain the session and clear it)
2-add a new object to a collection of the first object loaded previously
3-save the second object (clearing again the session and invoking saveOrUpdate)
4-flush the session

During the flush process we got the NullPointerException...

About the stacktrace... my program wasn't eating it.. it was jboss.. anyway.. found it..

14:12:17,169 INFO [STDOUT] java.lang.NullPointerException
14:12:17,173 INFO [STDOUT] at net.sf.hibernate.impl.SessionImpl.collectionIsDirty(SessionImpl.java:2982)
14:12:17,175 INFO [STDOUT] at net.sf.hibernate.impl.DirtyCollectionSearchVisitor.processCollection(DirtyCollectionSearchVisitor.java:50)
14:12:17,178 INFO [STDOUT] at net.sf.hibernate.impl.AbstractVisitor.processValue(AbstractVisitor.java:69)
14:12:17,180 INFO [STDOUT] at net.sf.hibernate.impl.AbstractVisitor.processValues(AbstractVisitor.java:36)
14:12:17,181 INFO [STDOUT] at net.sf.hibernate.impl.SessionImpl.isUpdateNecessary(SessionImpl.java:2611)
14:12:17,183 INFO [STDOUT] at net.sf.hibernate.impl.SessionImpl.flushEntity(SessionImpl.java:2526)
14:12:17,186 INFO [STDOUT] at net.sf.hibernate.impl.SessionImpl.flushEntities(SessionImpl.java:2458)
14:12:17,188 INFO [STDOUT] at net.sf.hibernate.impl.SessionImpl.flushEverything(SessionImpl.java:2260)
14:12:17,189 INFO [STDOUT] at net.sf.hibernate.impl.SessionImpl.flush(SessionImpl.java:2239)
14:12:17,191 INFO [STDOUT] at uy.edu.ort.persistence.HibernateMediator.save(HibernateMediator.java:87)
14:12:17,193 INFO [STDOUT] at uy.edu.ort.domain.manager.CompanyManager.save(CompanyManager.java:230)
14:12:17,195 INFO [STDOUT] at uy.edu.ort.domain.ejb.PropertyServicesBean.saveChoto(PropertyServicesBean.java:131)
14:12:17,197 INFO [STDOUT] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
14:12:17,199 INFO [STDOUT] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
14:12:17,201 INFO [STDOUT] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
14:12:17,203 INFO [STDOUT] at java.lang.reflect.Method.invoke(Method.java:324)
14:12:17,206 INFO [STDOUT] at org.jboss.ejb.StatelessSessionContainer$ContainerInterceptor.invoke(StatelessSessionContainer.java:683)
14:12:17,208 INFO [STDOUT] at org.jboss.resource.connectionmanager.CachedConnectionInterceptor.invoke(CachedConnectionInterceptor.java:185)
14:12:17,211 INFO [STDOUT] at org.jboss.ejb.plugins.StatelessSessionInstanceInterceptor.invoke(StatelessSessionInstanceInterceptor.java:72)
14:12:17,214 INFO [STDOUT] at org.jboss.ejb.plugins.AbstractTxInterceptor.invokeNext(AbstractTxInterceptor.java:84)
14:12:17,217 INFO [STDOUT] at org.jboss.ejb.plugins.TxInterceptorCMT.runWithTransactions(TxInterceptorCMT.java:315)
14:12:17,219 INFO [STDOUT] at org.jboss.ejb.plugins.TxInterceptorCMT.invoke(TxInterceptorCMT.java:148)
14:12:17,221 INFO [STDOUT] at org.jboss.ejb.plugins.SecurityInterceptor.invoke(SecurityInterceptor.java:120)
14:12:17,233 INFO [STDOUT] at org.jboss.ejb.plugins.LogInterceptor.invoke(LogInterceptor.java:191)
14:12:17,235 INFO [STDOUT] at org.jboss.ejb.plugins.ProxyFactoryFinderInterceptor.invoke(ProxyFactoryFinderInterceptor.java:122)
14:12:17,237 INFO [STDOUT] at org.jboss.ejb.StatelessSessionContainer.internalInvoke(StatelessSessionContainer.java:331)
14:12:17,240 INFO [STDOUT] at org.jboss.ejb.Container.invoke(Container.java:723)
14:12:17,241 INFO [STDOUT] at sun.reflect.GeneratedMethodAccessor154.invoke(Unknown Source)
14:12:17,244 INFO [STDOUT] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
14:12:17,246 INFO [STDOUT] at java.lang.reflect.Method.invoke(Method.java:324)
14:12:17,247 INFO [STDOUT] at org.jboss.mx.server.ReflectedDispatcher.dispatch(ReflectedDispatcher.java:60)
14:12:17,249 INFO [STDOUT] at org.jboss.mx.server.Invocation.dispatch(Invocation.java:61)
14:12:17,251 INFO [STDOUT] at org.jboss.mx.server.Invocation.dispatch(Invocation.java:53)
14:12:17,253 INFO [STDOUT] at org.jboss.mx.server.Invocation.invoke(Invocation.java:86)
14:12:17,255 INFO [STDOUT] at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:185)
14:12:17,257 INFO [STDOUT] at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:473)
14:12:17,260 INFO [STDOUT] at org.jboss.invocation.jrmp.server.JRMPInvoker.invoke(JRMPInvoker.java:360)
14:12:17,261 INFO [STDOUT] at sun.reflect.GeneratedMethodAccessor153.invoke(Unknown Source)
14:12:17,264 INFO [STDOUT] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
14:12:17,266 INFO [STDOUT] at java.lang.reflect.Method.invoke(Method.java:324)
14:12:17,268 INFO [STDOUT] at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:261)
14:12:17,269 INFO [STDOUT] at sun.rmi.transport.Transport$1.run(Transport.java:148)
14:12:17,272 INFO [STDOUT] at java.security.AccessController.doPrivileged(Native Method)
14:12:17,274 INFO [STDOUT] at sun.rmi.transport.Transport.serviceCall(Transport.java:144)
14:12:17,276 INFO [STDOUT] at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:460)
14:12:17,278 INFO [STDOUT] at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:701)
14:12:17,280 INFO [STDOUT] at java.lang.Thread.run(Thread.java:534)

I think I did check that "bug" a long time ago, but it was a user misuse of Hibernate, and I've managed not to fix that potential NPE.

I can't remember exactly why was the cause however.

Are you reassociating the same collection from 1 object to another or something odd like that.

Mmmmmmmmmm.... nope.."A" it's just a simple object with a couple of Lists, and "B" is just an object with a String (of course ids and timestamps), and i'm just putting "B" inside a collection in "A" (if it's already inside i'm not doing anything). I'm not doing anything odd at all..

We did a little trick that is working, but isn't what we need, if we open the session, load the object, close the session, open other session do the rest and close the session.. it works... but isn't the best...

are you working with a long session (storing it in httpSession for example)?

The session is really short.. just a few methods and i'm not using httpSession, i'm storing the session in a ThreadLocal and closing it at the end.

we keep trying different solutions for the problem and we removed the session.clear(), that fix the nullpointer but give us other problems.

Hey guys...

How about some code? That might help us diagnose the problem :)

I agree Steve,
I'm stick with my idea of a wrong Hibernate usage. Show us the code to find the problem.

We had the same exception when defining a "Set" in the java POJO, and map it it the mapping file with "list", which is obviously wrong. The exception is thrown if no data is changed, in a read-only operation.

Maybe this is a similar problem.

Anyway, the exception is rather obscure and hard to link directly to the collection type mismatch ..