When I started learning Spring, I noticed something about many of the tutorials I found.
They often showed how to use a feature, but not always why it worked or when you should choose one approach over another.
I learn best by building things and documenting what I discover, so I started a project called spring-by-example.
The idea is simple: instead of building one large application, I’m creating a collection of small, focused examples where each example explores a specific Spring concept with clear explanations, tests, and documentation.
I’m happy to say that I’ve now completed Module 5 — Bean Lifecycle. 🎉
The module covers:
InitializingBeanDisposableBean@PostConstruct@PreDestroyBeanPostProcessorBeanFactoryPostProcessorSmartLifecycle
One thing I’ve really enjoyed about this module is seeing how these concepts fit into different stages of the Spring container lifecycle.
For example, @PostConstruct and InitializingBean help with bean initialization, while @PreDestroy and DisposableBean provide ways to perform cleanup.
BeanPostProcessor introduced another interesting part of Spring: processing bean instances before and after initialization. BeanFactoryPostProcessor took that a step further by working with bean definitions before the actual bean instances are created.
And with SmartLifecycle, I explored how Spring can coordinate the startup and shutdown of components that have an active running state.
The goal isn’t just to collect Spring annotations and interfaces. I’m trying to understand how the Spring container works and why these features exist, one concept at a time.
The project is open source, and I’m continuing to build it as I learn:
🔗 GitHub: githu.b/mujuzimoses
There’s still a long way to go, but completing another module feels like a good milestone. 🚀
Next up: Events — exploring how Spring components can communicate through application events, including custom events, transactional events, and asynchronous events.
If you’ve worked with Spring before, what’s one part of the Spring bean lifecycle you think developers commonly misunderstand?
