In this chapter, we explored the fact that the main objective of the Business Delegate is to hide the details of service implementations from the presentation tier. We have also seen that, in some situations, its use has been replaced by CDI technology (this technology is responsible for injecting components into a typesafe way application, such as injecting an EJB component), but we believe that this is not enough. The Business Delegate is still widely used in the treatment of more technical exceptions—for example, when it has remote EJB calls. In addition, the delegate protects the presentation tier from possible changes in the service layer, and conversely, when there are types of clients other than a web browser, using a delegate makes it easier for these new clients to access services.
Session Façade centralizes business logic without exposing complex interactions that involve business objects to the client side. In addition, Session Façade encapsulates business-tier components...