java.lang.IllegalArgumentException：object不是在Hibernate中声明类的实例

Question

AfterCasting旧对象类型org.sakaiproject.tool.assessment.data.dao.assessment.AssessmentData@b7a641

在创建新对象类型org.sakaiproject.tool.assessment.data.dao.assessment.AssessmentData@16091af

之后

AfterCasting OLD Object CLASS org.sakaiproject.tool.assessment.data.dao.assessment.AssessmentData

AfterCasting NEW Object CLASS org.sakaiproject.tool.assessment.data.dao.assessment.AssessmentData

这些是我在下面为循环打印的陈述......

for(int i=0;i<pendingAssessdataList.size();i++)
        {
            AssessmentData ad=(AssessmentData)pendingAssessdataList.get(i);
            AssessmentData new_a = afq.prepareAssessment(ad, ServerConfigurationService.getServerUrl());    

openSession.save(new_a);
            }

在会话保存点（newObject）时，此异常会提升中止会话中对象的保存。 即使在实例相同之后，为什么它无法在会话中保存对象？