Your answer on the following questions would be gratly appreciated:

In page 39:

1-it is stated that to achieve isolation between J2EE-specific middle tire (EJBs) and rest of the application we should use interfaces as an abstract layer. Would you please let me know the place of this interfaces in our application.

View: JSP / XML
Controller: Servlet ------> Request Controllers(calling SessionBeans)
Model: EJBs

2-How come is it stated that implementation portability is not completely achievable in J2EE? We could have our application run on any J2EE compliant application server just by using the application server deployment descriptor file.



Best Regards,
Sam Emami