posted 12 years ago
I don't think this level of detail is required in sequence diagram. You can mention this is decisions section for improving performance.
The DAO/service layer will need to know what data is required by the web layer & will need to prefetch the data as Entity Manager will be closed/not availaible in web layer. Hibernate provides OpenSessionInViewInterceptor, which basically keeps the hibernate session open. Am not sure if something similar is availaible in JPA.