diff --git a/src/asciidoc/core-beans.adoc b/src/asciidoc/core-beans.adoc index 64082be6d8..7a76f3f1aa 100644 --- a/src/asciidoc/core-beans.adoc +++ b/src/asciidoc/core-beans.adoc @@ -4634,13 +4634,28 @@ If you intend to express annotation-driven injection by name, do not primarily u `@Autowired`, even if is technically capable of referring to a bean name through `@Qualifier` values. Instead, use the JSR-250 `@Resource` annotation, which is semantically defined to identify a specific target component by its unique name, with -the declared type being irrelevant for the matching process. +the declared type being irrelevant for the matching process. `@Autowired` has rather +different semantics: After selecting candidate beans by type, the specified String +qualifier value will be considered within those type-selected candidates only, e.g. +matching an "account" qualifier against beans marked with the same qualifier label. For beans that are themselves defined as a collection/map or array type, `@Resource` is a fine solution, referring to the specific collection or array bean by unique name. That said, as of 4.3, collection/map and array types can be matched through Spring's `@Autowired` type matching algorithm as well, as long as the element type information is preserved in `@Bean` return type signatures or collection inheritance hierarchies. +In this case, qualifier values can be used to select among same-typed collections, +as outlined in the previous paragraph. + +As of 4.3, `@Autowired` also considers self references for injection, i.e. references +back to the bean that is currently injected. Note that self injection is a fallback; +regular dependencies on other components always have precedence. In that sense, self +references do not participate in regular candidate selection and are therefore in +particular never primary; on the contrary, they always end up as lowest precedence. +In practice, use self references as a last resort only, e.g. for calling other methods +on the same instance through the bean's transactional proxy: Consider factoring out +the affected methods to a separate delegate bean in such a scenario. Alternatively, +use `@Resource` which may obtain a proxy back to the current bean by its unique name. `@Autowired` applies to fields, constructors, and multi-argument methods, allowing for narrowing through qualifier annotations at the parameter level. By contrast, `@Resource`