Explicit note on local bean access within @PostConstruct method

Closes gh-27876

Author: jhoeller

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
 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::
 ----
 ======
 
-
 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
 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