got the following exception while starting jboss (got it only once):

Caused by: java.util.ConcurrentModificationException
at java.util.HashMap$HashIterator.nextEntry(HashMap.java:793)
at java.util.HashMap$KeyIterator.next(HashMap.java:828)
at java.util.AbstractCollection.addAll(AbstractCollection.java:305)
at java.util.TreeSet.addAll(TreeSet.java:295)
at org.jboss.mx.loading.UnifiedLoaderRepository3.getPackageClassLoaders(UnifiedLoaderRepository3.java:251)
at org.jboss.mx.loading.LoadMgr3.beginLoadTask(LoadMgr3.java:178)
at org.jboss.mx.loading.RepositoryClassLoader.loadClassImpl(RepositoryClassLoader.java:521)
at org.jboss.mx.loading.RepositoryClassLoader.loadClass(RepositoryClassLoader.java:415)
at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)
at org.hibernate.engine.query.NativeSQLQueryPlan.<init>(NativeSQLQueryPlan.java:67)
at org.hibernate.engine.query.QueryPlanCache.getNativeSQLQueryPlan(QueryPlanCache.java:136)
at org.hibernate.impl.AbstractSessionImpl.getNativeSQLQueryPlan(AbstractSessionImpl.java:160)
at org.hibernate.impl.SessionImpl.executeNativeUpdate(SessionImpl.java:1182)
at org.hibernate.impl.SQLQueryImpl.executeUpdate(SQLQueryImpl.java:357)
at com.cxtrm.mgmt.sessionmgr.legacy.SessionManagerDMHOperatorBean.execUpdate(SessionManagerDMHOperatorBean.java:316)
at com.cxtrm.mgmt.sessionmgr.legacy.SessionManagerDMHOperatorBean.com$cxtrm$mgmt$sessionmgr$legacy$SessionManagerDMHOperatorBean$nativeMaintenance$aop(SessionManagerDMHOperatorBean.java:307)
at com.cxtrm.mgmt.sessionmgr.legacy.SessionManagerDMHOperatorBean$nativeMaintenance_N8100252910500966105.invokeNext(SessionManagerDMHOperatorBean$nativeMaintenance_N8100252910500966105.java)
at com.cxtrm.mgmt.aop.tx.TransactionRetrier.txRetryMarker(TransactionRetrier.java:34)
at org.jboss.aop.advice.com.cxtrm.mgmt.aop.tx.TransactionRetrier76.invoke(TransactionRetrier76.java)
at com.cxtrm.mgmt.sessionmgr.legacy.SessionManagerDMHOperatorBean$nativeMaintenance_N8100252910500966105.invokeNext(SessionManagerDMHOperatorBean$nativeMaintenance_N8100252910500966105.java)
at com.cxtrm.mgmt.sessionmgr.legacy.SessionManagerDMHOperatorBean.nativeMaintenance(SessionManagerDMHOperatorBean.java)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:112)
at org.jboss.ejb3.interceptor.InvocationContextImpl.proceed(InvocationContextImpl.java:166)
at org.jboss.ejb3.interceptor.EJB3InterceptorsInterceptor.invoke(EJB3InterceptorsInterceptor.java:63)
at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
at org.jboss.ejb3.entity.TransactionScopedEntityManagerInterceptor.invoke(TransactionScopedEntityManagerInterceptor.java:54)
at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
at org.jboss.ejb3.AllowedOperationsInterceptor.invoke(AllowedOperationsInterceptor.java:47)
at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
at org.jboss.aspects.tx.TxPolicy.org$jboss$aspects$tx$TxPolicy$invokeInOurTx$aop(TxPolicy.java:79)
... 67 more