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Explicit note on local bean access within @PostConstruct method

Closes gh-27876
pull/31301/merge
Juergen Hoeller 1 year ago
parent
commit
4cf5c7796d
  1. 9
      framework-docs/modules/ROOT/pages/core/beans/java/composing-configuration-classes.adoc

9
framework-docs/modules/ROOT/pages/core/beans/java/composing-configuration-classes.adoc

@ -113,7 +113,8 @@ issue, because no compiler is involved, and you can declare @@ -113,7 +113,8 @@ issue, because no compiler is involved, and you can declare
When using `@Configuration` classes, the Java compiler places constraints on
the configuration model, in that references to other beans must be valid Java syntax.
Fortunately, solving this problem is simple. As xref:core/beans/java/bean-annotation.adoc#beans-java-dependencies[we already discussed],
Fortunately, solving this problem is simple. As
xref:core/beans/java/bean-annotation.adoc#beans-java-dependencies[we already discussed],
a `@Bean` method can have an arbitrary number of parameters that describe the bean
dependencies. Consider the following more real-world scenario with several `@Configuration`
classes, each depending on beans declared in the others:
@ -204,7 +205,6 @@ Kotlin:: @@ -204,7 +205,6 @@ Kotlin::
----
======
There is another way to achieve the same result. Remember that `@Configuration` classes are
ultimately only another bean in the container: This means that they can take advantage of
`@Autowired` and `@Value` injection and other features the same as any other bean.
@ -216,6 +216,11 @@ classes are processed quite early during the initialization of the context, and @@ -216,6 +216,11 @@ classes are processed quite early during the initialization of the context, and
to be injected this way may lead to unexpected early initialization. Whenever possible, resort to
parameter-based injection, as in the preceding example.
Avoid access to locally defined beans within a `@PostConstruct` method on the same configuration
class. This effectively leads to a circular reference since non-static `@Bean` methods semantically
require a fully initialized configuration class instance to be called on. With circular references
disallowed (e.g. in Spring Boot 2.6+), this may trigger a `BeanCurrentlyInCreationException`.
Also, be particularly careful with `BeanPostProcessor` and `BeanFactoryPostProcessor` definitions
through `@Bean`. Those should usually be declared as `static @Bean` methods, not triggering the
instantiation of their containing configuration class. Otherwise, `@Autowired` and `@Value` may not

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