AssertionFailure occurs with listeners on models with many-to-many collection. ------------------------------------------------------------------------------- Key: HHH-443 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-443 Project: Hibernate3 Issue Type: Bug Components: core Affects Versions: 3.0.2 Environment: Hibernate version 3.0.2 Oracle9i Reporter: Tom Kucharski The problem occurs when insert or update listener is created on hibernate session on model with many-to-many collection and listener is making some queries with this model. The listener is needed for checking data integrity , so I need to make some select clauses within this listener. That is my code from PreInsertEventListener.onPreInsert() method (some lines were removed for clearance) : //I set this on FlushMode.NEVER because StackOverflowError is thrown event.getSession().setFlushMode(FlushMode.NEVER); // Function below makes database query using criteria API String o = listener.validate(event.getEntity(),event.getSession()); if (o != null) { // I don't know if this is correct, but why not?? I don't catch this exception in my code and I have auto_close_session and auto_flush_session on true throw new ConstraintViolationException(o,null,null); } // set to default settings event.getSession().setFlushMode(FlushMode.AUTO); That's exception from my WebLogic 8.1 server <2005-05-05 18:05:15 CEST> <Error> <org.hibernate.AssertionFailure> <000000> <an assertion failure occured (this may indicate a bug in Hibernate, but is more likely due to unsafe use of the session) org.hibernate.AssertionFailure: collection was not processed by flush() at org.hibernate.engine.CollectionEntry.postFlush(CollectionEntry.java:144) at org.hibernate.event.def.AbstractFlushingEventListener.postFlush(AbstractFlushingEventListener.java:305) at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:28) at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:678) at pl.softbank.cepik.modris.common.client.util.DefaultModrisClient.updateObject(DefaultModrisClient.java:196) at pl.softbank.cepik.modris.dict.common.client.CommonDictModrisClient.insert(CommonDictModrisClient.java:71)