Hibernate 启用延迟加载时保存时的NullPointerException（flush:true）

当我在Grails应用程序中为某些域类启用延迟加载（使用WebLogic）时，一些事务停止工作。代码总是在不同的阶段失败，但到目前为止，它只在save（flush:true）和findAll（）中失败，即使这些应用于甚至没有启用延迟加载的类。当我禁用所有类的延迟加载时，它可以正常工作。我知道flush：无论如何都应该避免使用true，但我不知道是什么导致了这个问题

java.lang.NullPointerException: null
    at org.hibernate.event.internal.AbstractFlushingEventListener.prepareEntityFlushes(AbstractFlushingEventListener.java:155)
    at org.hibernate.event.internal.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:91)
    at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:55)
    at org.hibernate.internal.SessionImpl.flush(SessionImpl.java:1258)
    at org.grails.orm.hibernate.AbstractHibernateGormInstanceApi.flushSession(AbstractHibernateGormInstanceApi.groovy:272)
    at sun.reflect.GeneratedMethodAccessor1101.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:93)
    at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325)
    at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1215)
    at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1024)
    at org.codehaus.groovy.runtime.InvokerHelper.invokePogoMethod(InvokerHelper.java:923)
    at org.codehaus.groovy.runtime.InvokerHelper.invokeMethod(InvokerHelper.java:906)
    at org.codehaus.groovy.runtime.InvokerHelper.invokeMethodSafe(InvokerHelper.java:74)
    at org.grails.orm.hibernate.AbstractHibernateGormInstanceApi$_performSave_closure3.doCall(AbstractHibernateGormInstanceApi.groovy:237)
    at sun.reflect.GeneratedMethodAccessor971.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:93)
    at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325)
    at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:294)
    at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1024)
    at groovy.lang.Closure.call(Closure.java:414)
    at org.codehaus.groovy.runtime.ConvertedClosure.invokeCustom(ConvertedClosure.java:54)
    at org.codehaus.groovy.runtime.ConversionHandler.invoke(ConversionHandler.java:124)
    at com.sun.proxy.$Proxy90.doInHibernate(Unknown Source)
    at org.grails.orm.hibernate.GrailsHibernateTemplate.doExecute(GrailsHibernateTemplate.java:196)
    at org.grails.orm.hibernate.GrailsHibernateTemplate.execute(GrailsHibernateTemplate.java:140)
    at org.grails.orm.hibernate.GrailsHibernateTemplate.execute(GrailsHibernateTemplate.java:110)
    at org.grails.orm.hibernate.AbstractHibernateGormInstanceApi.performSave(AbstractHibernateGormInstanceApi.groovy:234)
    at org.grails.orm.hibernate.AbstractHibernateGormInstanceApi.save(AbstractHibernateGormInstanceApi.groovy:154)
    at org.grails.datastore.gorm.GormEntity$Trait$Helper.save(GormEntity.groovy:151)
    at org.grails.datastore.gorm.GormEntity$Trait$Helper$save$17.call(Unknown Source)
    at [myOwnCode].save()
        [...]