Well to make things easier we shall agree that your systems is only implementing a very basic loan system that allows users to check their status online. They can check their transactions history as well as the overall credit score and they could also receive promotional offers from the same financial institution. Your application is not responsible to update the database with loan specific data, like payments, credit score information, etc and we shall agree that there is another external system that does all these operations (you might run a set of sql to do this manually). Your application however is capable to update and maintain user�s profile information, like address, phone numbers, ssn, first name, last name, etc.
If you do agree with this limited set of ad-hoc requirements, I�ll have to ask you to start with the beginning: design your data model. Please identify the data structures that you need to use and come up with your data model, mostly like a set of tables in the database and we shall see from there. I�ll mostly help you implementing the business logic and probably we�d like to use entity ejbs for mapping to your data model (just for the sake of exercise) and a session fa�ade
pattern. You�d also like using code generation tools like XDoclet or ejbgen for simplifying the ejb development. There are several design strategies that you�d like to employee, like using service locator or value objects paradigms, etc.
Regards.