Understanding the most common JEE APIs

Now that we have seen an overview of the JEE technology and implemented it with application servers, we will learn about the most common JEE APIs that are used in enterprise projects. We will have a look at some examples of those APIs at the end of this chapter, in the Case studies and examples section.

Dependency injection

I remember the times when dependency injection was simply not available in JEE, and we had to rely exclusively on EJB version 2 (unfortunately) to wire our dependencies. This was probably one of the reasons behind the growth in popularity of the Spring Framework, which became widespread by offering a lightweight alternative to wiring, based on dependency injection, and avoiding verbose and error-prone configuration files. But that's another story that is out of the scope of this book.

Dependency Injection (DI) or Contexts and Dependency Injection (CDI) is a concept that extends and implements the Inversion of...