I have e 3 tier application, (client-app-server-db, no web-server is used) with many mapped class (at now they are 254) and it works perfectly with Hibernate 2.1.6.

Now we're trying to migrate to Hibernate3 (and it's related lib), but I have an out of memory exception while Hibernare is creating the sessionFactory.

This is a part of the stack-trace:

16:42:47,734 ERROR [BasicLazyInitializer] CGLIB Enhancement failed: [myClassName]
java.lang.ExceptionInInitializerError
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:324)
at net.sf.cglib.proxy.Enhancer.setCallbacksHelper(Enhancer.java:586)
at net.sf.cglib.proxy.Enhancer.setThreadCallbacks(Enhancer.java:579)
at net.sf.cglib.proxy.Enhancer.createUsingReflection(Enhancer.java:601)
at net.sf.cglib.proxy.Enhancer.firstInstance(Enhancer.java:532)
at net.sf.cglib.core.AbstractClassGenerator.create(AbstractClassGenerator.java:220)
at net.sf.cglib.proxy.Enhancer.createHelper(Enhancer.java:373)
at net.sf.cglib.proxy.Enhancer.create(Enhancer.java:281)
at net.sf.cglib.proxy.Enhancer.create(Enhancer.java:640)
at org.hibernate.proxy.CGLIBLazyInitializer.getProxyFactory(CGLIBLazyInitializer.java:94)
at org.hibernate.proxy.CGLIBProxyFactory.postInstantiate(CGLIBProxyFactory.java:42)
at org.hibernate.tuple.PojoTuplizer.buildProxyFactory(PojoTuplizer.java:144)
at org.hibernate.tuple.AbstractTuplizer.<init>(AbstractTuplizer.java:83)
at org.hibernate.tuple.PojoTuplizer.<init>(PojoTuplizer.java:54)
at org.hibernate.tuple.TuplizerLookup.create(TuplizerLookup.java:47)
at org.hibernate.tuple.EntityMetamodel.<init>(EntityMetamodel.java:218)
at org.hibernate.persister.entity.BasicEntityPersister.<init>(BasicEntityPersister.java:400)
at org.hibernate.persister.entity.SingleTableEntityPersister.<init>(SingleTableEntityPersister.java:104)
at org.hibernate.persister.PersisterFactory.createClassPersister(PersisterFactory.java:55)
at org.hibernate.impl.SessionFactoryImpl.<init>(SessionFactoryImpl.java:211)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1005)
...
[omissis]
...
Caused by: net.sf.cglib.core.CodeGenerationException: java.lang.reflect.InvocationTargetException-->null
at net.sf.cglib.core.AbstractClassGenerator.create(AbstractClassGenerator.java:236)
at net.sf.cglib.reflect.FastClass$Generator.create(FastClass.java:67)
at net.sf.cglib.proxy.MethodProxy.helper(MethodProxy.java:81)
at net.sf.cglib.proxy.MethodProxy.create(MethodProxy.java:47)
at [myClassName]$$EnhancerByCGLIB$$5a2d02e0.CGLIB$STATICHOOK195(<generated>)
at [myClassName]$$EnhancerByCGLIB$$5a2d02e0.<clinit>(<generated>)
... 87 more
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.GeneratedMethodAccessor72.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:324)
at net.sf.cglib.core.ReflectUtils.defineClass(ReflectUtils.java:373)
at net.sf.cglib.core.AbstractClassGenerator.create(AbstractClassGenerator.java:218)
... 92 more
Caused by: java.lang.OutOfMemoryError

Note that everytime [myClassName] changes, so it's not here the problem.

This occurs both with Orion 9.5.1 and JBoss 3.2.5.

I've try to change the hibernate.cache.provider_class value (which now is org.hibernate.cache.TreeCacheProvider), but the error is always an OutOfMemoryError.
I've also try to increase the memory for the app-server with -Xms128m -Xmx1024m parameters for the app-server, but nothing changes.

Any ideas or suggestions?
Regards
Alessandro Rizzi

"Lazy" is default in hibernate3 and probably CGLIB will generate more stuff, it needs permatent memory:

http://forum.hibernate.org/viewtopic.php?t=943395

GREAT! Now it works again.

many, many, many thanks
Alessandro