Extend the "bootstrap = BACKGROUND" mechanism to Component-scanned beans

[djechelon]

I am very enthusiast about Spring 6.2 feaute of Bean Background Initialization implemented via @Bean annotation.

However, I would suggest to extend it also to @Component-scanned beans. I have an application with thousands of beans, and I am working on improving its startup time. Basically, while I have benefitted from @Bean(bootstrap = BACKGROUND) for @Configuration-factored bean, it is not convenient to refactor a number of @Component beans into @Bean beans for reasons of simplicity.

Implementing the bootstrap = BACKGROUND attribute into @Component and derivatives seems to me to be the next step.

Any thoughts on this?

[jhoeller]

I'm afraid that we have no such plans. Component scanning is a decentralized stereotype model, concrete bootstrapping definitions would arguably not really fit there. We do actually recommend defining such beans in @Bean methods instead.

For a large number of scanned beans, you could implement a BeanFactoryPostProcessor that sets the backgroundInit flag on corresponding BeanDefinition instances based on some policy, for example based on naming or a custom annotation.