1) Hi Esteban.It is a great question. And the answer to your question is: both approaches are correct. In the book, the original object oriented patterns and its adaptations for the Java EE 8 context have been shown, such as for example The Session Façade Pattern and the GoF Facade. Anothe example we can see is the Aspect Design Pattern, where we show the implementation of the Decorator Pattern in the Java EE context.
On the other hand, we put in the book new concepts and patterns used to follow the evolution of systems development, such as Microservice pattern used for the functional decomposition of an application.
2) Another good question, Esteban. Again, both things. We discuss how the use of patterns provides code reuse, low coupling, and improves system maintenance (The chapter on business pattern is an excellent example of this). But you will see throughout the book, the advantages and disadvantages of using some patterns in the development of an application. We also show you how to apply certain patterns to improve the deployment (for example Microservice pattern) and performance. In the cloud native application pattern, for example, we show the use of methodologies and care when developing a cloud application (Where service instances are always being created and destroyed).