Document programmatic bean registration

This commit adds the reference documentation for the new programmatic
bean registration capabilities for both Java and Kotlin.

Closes gh-18353

framework-docs/modules/ROOT/pages/languages/kotlin/bean-definition-dsl.adoc

@@ -1,113 +1,7 @@
 [[kotlin-bean-definition-dsl]]
 = Bean Definition DSL
 
-Spring Framework supports registering beans in a functional way by using lambdas
-as an alternative to XML or Java configuration (`@Configuration` and `@Bean`). In a nutshell,
-it lets you register beans with a lambda that acts as a `FactoryBean`.
-This mechanism is very efficient, as it does not require any reflection or CGLIB proxies.
-
-In Java, you can, for example, write the following:
-
-[source,java,indent=0]
-----
-	class Foo {}
-
-	class Bar {
-		private final Foo foo;
-		public Bar(Foo foo) {
-			this.foo = foo;
-		}
-	}
-
-	GenericApplicationContext context = new GenericApplicationContext();
-	context.registerBean(Foo.class);
-	context.registerBean(Bar.class, () -> new Bar(context.getBean(Foo.class)));
-----
-
-In Kotlin, with reified type parameters and `GenericApplicationContext` Kotlin extensions,
-you can instead write the following:
-
-[source,kotlin,indent=0]
-----
-	class Foo
-
-	class Bar(private val foo: Foo)
-
-	val context = GenericApplicationContext().apply {
-		registerBean<Foo>()
-		registerBean { Bar(it.getBean()) }
-	}
-----
-
-When the class `Bar` has a single constructor, you can even just specify the bean class,
-the constructor parameters will be autowired by type:
-
-[source,kotlin,indent=0]
-----
-	val context = GenericApplicationContext().apply {
-		registerBean<Foo>()
-		registerBean<Bar>()
-	}
-----
-
-In order to allow a more declarative approach and cleaner syntax, Spring Framework provides
-a {spring-framework-api-kdoc}/spring-context/org.springframework.context.support/-bean-definition-dsl/index.html[Kotlin bean definition DSL]
-It declares an `ApplicationContextInitializer` through a clean declarative API,
-which lets you deal with profiles and `Environment` for customizing
-how beans are registered.
-
-In the following example notice that:
-
-* Type inference usually allows to avoid specifying the type for bean references like `ref("bazBean")`
-* It is possible to use Kotlin top level functions to declare beans using callable references like `bean(::myRouter)` in this example
-* When specifying `bean<Bar>()` or `bean(::myRouter)`, parameters are autowired by type
-* The `FooBar` bean will be registered only if the `foobar` profile is active
-
-[source,kotlin,indent=0]
-----
-	class Foo
-	class Bar(private val foo: Foo)
-	class Baz(var message: String = "")
-	class FooBar(private val baz: Baz)
-
-	val myBeans = beans {
-		bean<Foo>()
-		bean<Bar>()
-		bean("bazBean") {
-			Baz().apply {
-				message = "Hello world"
-			}
-		}
-		profile("foobar") {
-			bean { FooBar(ref("bazBean")) }
-		}
-		bean(::myRouter)
-	}
-
-	fun myRouter(foo: Foo, bar: Bar, baz: Baz) = router {
-		// ...
-	}
-----
-
-NOTE: This DSL is programmatic, meaning it allows custom registration logic of beans
-through an `if` expression, a `for` loop, or any other Kotlin constructs.
-
-You can then use this `beans()` function to register beans on the application context,
-as the following example shows:
-
-[source,kotlin,indent=0]
-----
-	val context = GenericApplicationContext().apply {
-		myBeans.initialize(this)
-		refresh()
-	}
-----
-
-NOTE: Spring Boot is based on JavaConfig and
-{spring-boot-issues}/8115[does not yet provide specific support for functional bean definition],
-but you can experimentally use functional bean definitions through Spring Boot's `ApplicationContextInitializer` support.
-See {stackoverflow-questions}/45935931/how-to-use-functional-bean-definition-kotlin-dsl-with-spring-boot-and-spring-w/46033685#46033685[this Stack Overflow answer]
-for more details and up-to-date information. See also the experimental Kofu DSL developed in {spring-github-org}-experimental/spring-fu[Spring Fu incubator].
+See xref:core/beans/java/programmatic-bean-registration.adoc[Programmatic Bean Registration].