Dependency injection frameworks such as Spring, Quarkus, and others support dependency injection by using annotations such as @Inject
and @Autowired. These annotations can be used to inject beans via constructor, setter, and field injection.
Generally speaking, field injection is discouraged. It allows the creation of objects in an invalid state and makes testing more difficult. The
dependencies are not explicit when instantiating a class that uses field injection.
In addition, field injection is not compatible with final fields. Keeping dependencies immutable where possible makes the code easier to
understand, easing development and maintenance.
Finally, because values are injected into fields after the object has been constructed, they cannot be used to initialize other non-injected fields
inline.
This rule raises an issue when the @Autowired or @Inject annotations are used on a field.
