Java Reference
In-Depth Information
Chapter 5. The Business Layer
Here we will begin with a presentation of improvements in the business layer and
then, in a small project, we will try to put together some of the specifications seen pre-
viously. The topics to be covered include:
• Enterprise JavaBeans 3.2
• Putting all Java EE 7 specifications together
Enterprise JavaBeans 3.2
The Enterprise JavaBeans 3.2 Specification was developed under JSR 345. This sec-
tion just gives you an overview of improvements in the API. The complete document
specification (for more information) can be downloaded from
communityprocess/final/jsr345/index.html .
The business layer of an application is the part of the application that is located
between the presentation layer and data access layer. The following diagram
presents a simplified Java EE architecture. As you can see, the business layer acts
as a bridge between the data access and the presentation layer.
It implements business logic of the application. To do so, it can use some specific-
ations such as Bean Validation for data validation, CDI for context and dependency
injection, interceptors to intercept processing, and so on. As this layer can be located
anywhere in the network and is expected to serve more than one user, it needs a min-
imum of non functional services such as security, transaction, concurrency, and re-
mote access management. With EJBs, the Java EE platform provides to developers
the possibility to implement this layer without worrying about different non functional
services that are necessarily required.
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