Overview (Jakarta Context Dependency Injection API)

Packages
Package	Description
javax.decorator	Annotations relating to decorators.
javax.enterprise.context	Annotations and interfaces relating to scopes and contexts.
javax.enterprise.context.control
javax.enterprise.context.spi	The custom context SPI.
javax.enterprise.event	Annotations and interfaces relating to events.
javax.enterprise.inject
javax.enterprise.inject.literal
javax.enterprise.inject.se
javax.enterprise.inject.spi	The portable extension integration SPI.
javax.enterprise.inject.spi.configurator
javax.enterprise.util	Contains shared, general-purpose helper classes and annotations.

Jakarta Contexts and Dependency Injection (CDI) defines a set of complementary services that help improve the structure of application code.

A well-defined lifecycle for stateful beans bound to well-defined lifecycle contexts, where the set of contexts is extensible
A sophisticated, typesafe dependency injection mechanism, including the ability to select dependencies at either development or deployment time, without verbose configuration
Support for Jakarta EE modularity and the Jakarta EE component architecture—the modular structure of a Java EE application is taken into account when resolving dependencies between Java EE components
Integration with the Jakarta Expression Language, allowing any bean to be used directly within a Jakarta Server Faces or Jakarta Server Page page
The ability to decorate injected beans
The ability to associate interceptors with beans via typesafe interceptor bindings
An event notification model
A web conversation context in addition to the three standard web contexts defined by the Jakarta Servlet specification
An SPI allowing portable extensions to integrate cleanly with the container

CDI allows objects to be bound to lifecycle contexts, to be injected, to be associated with interceptors and decorators, and to interact in a loosely coupled fashion by firing and observing events. Various kinds of objects are injectable, including EJB 3 session beans, managed beans, producer methods and Jakarta EE resources. We refer to these objects in general terms as beans and to instances of beans that are bound to contexts as contextual instances.