org.springframework.config.java.annotation
Annotation Type Bean

@Target(value=METHOD)
@Retention(value=RUNTIME)
public @interface Bean

Annotation to be applied to methods that create beans in a Spring context. The name of the bean is the method name. (It is also possible to specify aliases using the aliases array on this annotation.)

Contains similar information to that held in Spring's internal BeanDefinition metadata.

Bean creation methods must be public or protected. Bean creation methods may throw any exception, which will be caught and handled by the Spring container on processing of the configuration class.
Bean creation methods must return an object type. The decision to return a class or an interface will be significant in the event of proxying. Bean methods that return interfaces will be proxied using dynamic proxies; those that return a class will require CGLIB or other subclass-based proxying. Return an interface as possible, as this is also consistent with best practice around loose coupling.

Bean creation methods may reference other bean creation methods by calling them directly, as follows. This ensures that references between beans are strongly typed:

 @Bean
 public Company interface21() {
    Company company = new DefaultCompany("Interface21");
    company.setChiefScientist(adrian());
    return company;
 }
 
 @Bean
 public Person adrian() {
    return new Person("Adrian Colyer");
 }
 

If a bean creation method is protected, rather than public, the the bean will be hidden. This means that the bean will be added to a child factory used internally by the ConfigurationProcessor, rather than the main factory, meaning it won't be visible to other definitions. This is particularly useful for Spring AOP Advisors or AspectJ aspects, which might otherwise alter behaviour of the owning factory as a whole.

Author:

Rod Johnson, Costin Leau

See Also:

Configuration

Optional Element Summary

java.lang.String[]	aliases Bean aliases.
boolean	allowOverriding Allow the bean to be overridden in XML or other non-Java configuration
org.springframework.beans.factory.annotation.Autowire	autowire Bean autowire strategy.
DependencyCheck	dependencyCheck Bean dependency check strategy.
java.lang.String[]	dependsOn Beans on which the current bean depends on.
java.lang.String	destroyMethodName Bean destroy method name.
java.lang.String	initMethodName Bean init method name.
Lazy	lazy Bean lazy strategy.
Meta[]	meta Metadata for the current bean.
java.lang.String	scope Scope: whether the bean is a singleton, prototype or custom scope.

aliases

public abstract java.lang.String[] aliases

Bean aliases.

Default:

{}

scope

public abstract java.lang.String scope

Scope: whether the bean is a singleton, prototype or custom scope. Default is singleton.

Default:

"singleton"

autowire

public abstract org.springframework.beans.factory.annotation.Autowire autowire

Bean autowire strategy.

Default:

INHERITED

lazy

public abstract Lazy lazy

Bean lazy strategy.

Default:

UNSPECIFIED

initMethodName

public abstract java.lang.String initMethodName

Bean init method name. Normally this is not needed, as the initialization (with parameterization) can be done directly through java code.

Default:

""

destroyMethodName

public abstract java.lang.String destroyMethodName

Bean destroy method name.

Default:

""

dependencyCheck

public abstract DependencyCheck dependencyCheck

Bean dependency check strategy.

Default:

UNSPECIFIED

dependsOn

public abstract java.lang.String[] dependsOn

Beans on which the current bean depends on.

Default:

{}

meta

public abstract Meta[] meta

Metadata for the current bean.

Default:

{}

allowOverriding

public abstract boolean allowOverriding

Allow the bean to be overridden in XML or other non-Java configuration

Returns:

whether overriding of this bean is allowed

Default:

false