@Required doesn't play nice with @Configuration and @Bean [SPR-5744]

[spring-projects-issues]

Kenny MacLeod opened SPR-5744 and commented

I've been using M3 to try porting fragments of existing applications to use @Configuration and @Bean instead of XML bean definitions. The bean classes make heavy use of @Required. When I try to configure one of these beans using annotations, and injecting collaborators java-style, the context fails to start up, saying that a @Required property has not been set.

This is a problem, because these existing application classes are used everywhere, mostly using the @Required annotation in conjunction with XML bean definitions. Also, the context:component-scan tag which is used to locate the @Configuration classes implicitly adds a RequiredAnnotationBeanPostProcessor to the context.

It's not clear how to handle this, unless the framework can automagically figure out that the @Bean method is injecting the collaborators.

I've created a standalone test case illustrating the problem.

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Affects: 3.0 M3

Attachments:

• test.zip (1.33 kB)

Referenced from: commits c7b019c

[spring-projects-issues]

Juergen Hoeller commented

Good point! I've simply suppressed @Required processing for beans returned by @Bean factory methods. We cannot reliably check whether the property has been injected in that case; arguably @Required isn't really designed for that purpose to begin with. However, it shouldn't cause failures either.

Juergen