We are presuming that the reader knows the basic characteristics that surround the CDI, as well as its main objectives and uses. However, it is very important to emphasize some definitions and aspects of the CDI.

The CDI technology is one of the pillars of the JEE platform, and it is present in most of its services. This means that these services depend in some way on the CDI mechanism—CDI is closely related to the bean concept within the EE specification, so let's take a look at what a bean actually is.