I've been reading this sample these days to learn how to build a J2EE application. But I losed my way in this sample. The structure is too complicated. First, establish 3 entity beans. Second, use a stateless session bean named ServerDateModule to use the established entity beans. Third, use a stateful session bean named Cart to use the stateless bean then in the web layer, use a ClientDateModule bean to connect the session bean Cart then again, use a bean named SessionBean to use the ClientDateModule finally, use servlet and Jsp to use the SessionBean Why so complicated? Borland JBuilder use a lot of their own technique to implement this sample, such as EntityBeanProvider, EntityBeanResolver, DataSet..., and they claim that will improve the efficiency. really?? I don't know if this kind of structure is popular in design a J2EE application. Because I'm a newbie, i do need advice from expert. help me!