Summary

Engineers are advised to focus on the domain and business logic first, by starting from the use case boundaries and stepping down the abstraction layers. Java EE core domain components, namely EJBs, CDI, CDI producers and events, are used to implement the plain business logic. Other Java EE APIs are mainly used to support the business logic in technical necessities. As we have seen, Java EE implements and encourages numerous software design patterns as well as the approaches of Domain-Driven Design in modern ways.

We have seen how to choose and implement communication, in both synchronous and asynchronous ways. The communication technology depends on the business requirements. Especially HTTP is widely used and well-supported in Java EE via JAX-RS. REST is a prime example of an communication protocol architectural style that supports to loosely couple system.

Java EE ships with functionality that implements and enables technical cross-cutting concerns such as managed persistence, configuration...