Spring Tips: Programmatic Bean Registration in Spring Framework 5.0

Speaker: Josh Long
/ starbuxman
Hi Spring fans! in this installment, we'll look at different ways to register beans with Spring, culminating in the new programmatic bean registration functionality in Spring 5.

[@Hakucho64]

Hey Josh, nice presentation as usual. I was hoping there was going to be new support for switching bean implementations at runtime, after the application has been running for a while, e.g. in response to some change in the environment. What's the best way to do that please?

[@aakoss]

Would feature toggles be useful in such situations?

[@Hakucho64]

Yes, my question to Josh was more about how to get the Spring application context to start providing one implementation of some interface instead of another, e.g. at startup you might register a NoOpPersonServiceImpl under the PersonService interface, then in response to some environmental change, switch that bean to be backed by some other implementation, e.g. a DatabaseBackedPersonServiceImpl.

[@vinu_varghese]

Nice feature, is it possible to use the registerBean while the app is running via the reference to the applicationContext

[@aakoss]

Yes this is possible with a handle to the bean factory. However the context would need to be refreshed for any effect at runtime. This needs to be carefully and infrequently if not rare.