I am using seam 1.2.0 and integrate it with Ajax4Jsf in the project. My question is when i modified calculation from 1 to 2 in the page , i need to modify the paramters list (Annotated by DataModel) by ajax request. my codes are as follows: @DataModel private List runParameters; @Begin(join = true) @Factory("runParameters") public void findRunParameters() throws ClassNotFoundException { ....some codes to get the runParameters list through hibernate3 } the action will be called by ajax is: public void changeDropdownForCalculation(ActionEvent event) throws Exception { ...... findRunParameters(); } now you can see that i am using findRunParameters() to modify the list directly , but but i got the exception as follows: Caused by: org.hibernate.HibernateException: identifier of an instance of com.ogentech.cpi.dataobjects.calculation.Calculation was altered from 1 to 2 Can someone help me? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4047811#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...