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@ -37,18 +37,18 @@ Kotlin::
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----
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======
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[NOTE]
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[TIP]
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====
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As of Spring Framework 4.3, an `@Autowired` annotation on such a constructor is no longer
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necessary if the target bean defines only one constructor to begin with. However, if
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several constructors are available and there is no primary/default constructor, at least
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one of the constructors must be annotated with `@Autowired` in order to instruct the
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container which one to use. See the discussion on
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xref:core/beans/annotation-config/autowired.adoc#beans-autowired-annotation-constructor-resolution[constructor resolution] for details.
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An `@Autowired` annotation on such a constructor is not necessary if the target bean
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defines only one constructor. However, if several constructors are available and there is
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no primary or default constructor, at least one of the constructors must be annotated
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with `@Autowired` in order to instruct the container which one to use. See the discussion
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on xref:core/beans/annotation-config/autowired.adoc#beans-autowired-annotation-constructor-resolution[constructor resolution]
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for details.
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====
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You can also apply the `@Autowired` annotation to _traditional_ setter methods,
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as the following example shows:
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You can apply the `@Autowired` annotation to _traditional_ setter methods, as the
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following example shows:
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[tabs]
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======
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@ -84,8 +84,8 @@ Kotlin::
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----
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======
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You can also apply the annotation to methods with arbitrary names and multiple
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arguments, as the following example shows:
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You can apply `@Autowired` to methods with arbitrary names and multiple arguments, as the
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following example shows:
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[tabs]
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======
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@ -176,14 +176,15 @@ Kotlin::
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====
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Make sure that your target components (for example, `MovieCatalog` or `CustomerPreferenceDao`)
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are consistently declared by the type that you use for your `@Autowired`-annotated
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injection points. Otherwise, injection may fail due to a "no type match found" error at runtime.
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injection points. Otherwise, injection may fail due to a "no type match found" error at
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runtime.
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For XML-defined beans or component classes found via classpath scanning, the container
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usually knows the concrete type up front. However, for `@Bean` factory methods, you need
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to make sure that the declared return type is sufficiently expressive. For components
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that implement several interfaces or for components potentially referred to by their
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implementation type, consider declaring the most specific return type on your factory
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method (at least as specific as required by the injection points referring to your bean).
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implementation type, declare the most specific return type on your factory method (at
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least as specific as required by the injection points referring to your bean).
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====
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.[[beans-autowired-annotation-self-injection]]Self Injection
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@ -312,8 +313,8 @@ through `@Order` values in combination with `@Primary` on a single bean for each
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====
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Even typed `Map` instances can be autowired as long as the expected key type is `String`.
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The map values contain all beans of the expected type, and the keys contain the
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corresponding bean names, as the following example shows:
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The map values are all beans of the expected type, and the keys are the corresponding
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bean names, as the following example shows:
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[tabs]
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======
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@ -431,7 +432,7 @@ annotated constructor does not have to be public.
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====
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Alternatively, you can express the non-required nature of a particular dependency
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through Java 8's `java.util.Optional`, as the following example shows:
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through Java's `java.util.Optional`, as the following example shows:
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[source,java,indent=0,subs="verbatim,quotes"]
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----
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@ -445,8 +446,8 @@ through Java 8's `java.util.Optional`, as the following example shows:
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----
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You can also use a parameter-level `@Nullable` annotation (of any kind in any package --
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for example, `javax.annotation.Nullable` from JSR-305) or just leverage Kotlin built-in
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null-safety support:
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for example, `org.jspecify.annotations.Nullable` from JSpecify) or just leverage Kotlin's
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built-in null-safety support:
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[tabs]
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======
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@ -477,13 +478,6 @@ Kotlin::
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----
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======
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[NOTE]
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====
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A type-level `@Nullable` annotation such as from JSpecify is not supported in Spring
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Framework 6.2 yet. You need to upgrade to Spring Framework 7.0 where the framework
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detects type-level annotations and consistently declares JSpecify in its own codebase.
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====
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You can also use `@Autowired` for interfaces that are well-known resolvable
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dependencies: `BeanFactory`, `ApplicationContext`, `Environment`, `ResourceLoader`,
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`ApplicationEventPublisher`, and `MessageSource`. These interfaces and their extended
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@ -528,5 +522,6 @@ class MovieRecommender {
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The `@Autowired`, `@Inject`, `@Value`, and `@Resource` annotations are handled by Spring
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`BeanPostProcessor` implementations. This means that you cannot apply these annotations
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within your own `BeanPostProcessor` or `BeanFactoryPostProcessor` types (if any).
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These types must be 'wired up' explicitly by using XML or a Spring `@Bean` method.
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====
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