It is time to put everything together into a concrete banking application. This application is naturally not something your local bank would want to implement to support its business, but it does illustrate all of the key concepts I have covered in this book. The application is specifically a simple user interface that enables you to view your accounts and transfer money between any of them. It is a three-tier application that takes advantage of the Network Application Architecture, but it is not EJB-based. You will therefore have to construct tools along the way that you get for free with EJB. As a result, you will get a very practical feel for all the issues involved in distributed software development that you can apply to both EJB and nonEJB development.
With a distributed enterprise application, your starting point is the middle tier. The business classes that make up the middle tier are the key to a successful design. It is therefore the starting point for your development efforts. Figure 7.10 is a UML class diagram describing the mid-tier business objects for the banking application. You will build these objects in Chapter 8.
Figure 7-10. The middle tier of the banking application
Persistence is a huge topic. A distributed application that persists its objects against a relational database has so many complex issues, ...