Enterprise JavaBean (EJB) Model 

The Web Dynpro model importer supports the Common Model Interface (CMI). CMI is a layer of indirection between a framework like Web Dynpro Java, that uses a model, and a framework which implements a model, in this case the Enterprise JavaBean model. Both the using and the implementing framework are independent. Nevertheless they can exchange data via data binding, for instance.

Regarding the model, the layer grants a framework like Web Dynpro access to the business logic. It exposes business data and metadata via the CMI to the framework that sits on top of the CMI. For typed models, the structure is at least partially known at design time, and design time meta data is available. You can bind context nodes to model classes at design time and program in a type safe manner against these models. There is no urgent need for CMI metadata at runtime. For the generic models it is typical that the structure is unknown or at least not stable at design time. The CMI metadata must be available at runtime. There is only a dynamic binding between context node and model class at runtime, and no generation step is needed. The Enterprise Java Bean model allows mixtures between these two model types.

The EJB 3.0 standard is a powerful Java Enterprise Edition (EE) technology for business components where Java Persistence API contributes to a simplification of creating and using Enterprise JavaBeans. This leads for example to a light model building library, and with a minimum of custom code, you can call methods on the Enterprise JavaBean and can bind the results directly to Web Dynpro user interface elements. For one Web Dynpro application, you would use one or more Enterprise JavaBeans where these Enterprise JavaBeans are part of a Enterprise JavaBean Development Component.