我的线程执行时，有时会收到这个奇怪的错误。这可能与什么有关？

2011-Jun-25 09:05:22,339 ERROR AssertionFailure:45 - 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: null id in com.inrev.bm.bean.IRKeyWordTweet entry (don't flush the Session after an exception occurs)
    at         org.hibernate.event.def.DefaultFlushEntityEventListener.checkId(DefaultFlushEntityEventListener.java:78)
at org.hibernate.event.def.DefaultFlushEntityEventListener.getValues(DefaultFlushEntityEventListener.java:187)
at org.hibernate.event.def.DefaultFlushEntityEventListener.onFlushEntity(DefaultFlushEntityEventListener.java:143)
at org.hibernate.event.def.AbstractFlushingEventListener.flushEntities(AbstractFlushingEventListener.java:219)
at org.hibernate.event.def.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:99)
at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:49)
at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1028)
at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:366)
at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:137)
at com.inrev.bm.streaming.IRKeyWordStreaminThread.run(IRKeyWordStreaminThread.java:119)

我的插入代码

    Transaction tx = null;
    Session session = sessionFactory.openSession();
    tx = session.beginTransaction();

    int count = 0;
    try
    {
        for (Iterator itrList = statusToInsert.iterator(); itrList.hasNext();) 
        {
            try 
            {
                IRecord record = (IRecord) itrList.next();
                session.save(record);
                count++;
                if ( count % 10 == 0 ) 
                { 
                    session.flush();
                    session.clear();
                    tx.commit();
                    tx = session.beginTransaction();
                }

            }
            catch (Exception e) 
            {
                tx.commit();
                session.close();
                session = sessionFactory.openSession();
                tx = session.beginTransaction();
                StringWriter sw = new StringWriter(); 
                PrintWriter pw = new PrintWriter(sw); 
                e.printStackTrace(pw); 
                log.error(sw.toString());
            }
        }
    }
    catch (Exception e) {
        StringWriter sw = new StringWriter(); 
        PrintWriter pw = new PrintWriter(sw); 
        e.printStackTrace(pw); 
        log.error(sw.toString());
    }
    finally {
        tx.commit();
        session.close();
    }

问候，

罗希特