Hello devs! 👋
If you’re working with Spring Boot, understanding its lifecycle stages will help you build more maintainable and production-ready applications. In this post, I’ll break down the 7 key stages — with a simple diagram I created — so you can hook your code at the right time!
🌟 The 7 Stages of Spring Boot Lifecycle
1️⃣ Application Startup
The entry point — Spring Boot starts initializing the application, setting up essential resources.
2️⃣ Environment Preparation
Spring Boot prepares the environment, loading properties and profiles that affect the app's configuration.
3️⃣ ApplicationContext Creation
The ApplicationContext is created — the heart of Spring's DI container.
4️⃣ Bean Creation and Dependency Injection
Beans are instantiated, dependencies are injected, and Spring wires your app together.
5️⃣ Bean Initialization
Post-construct methods, @PostConstruct, and custom initialization logic are triggered.
6️⃣ Application Ready and Running
Your application is fully started — listeners like ApplicationReadyEvent are fired. Time to serve requests!
7️⃣ Graceful Shutdown
When you stop the app, Spring ensures resources are cleaned up properly (e.g., closing connections).
💡 Why Care About the Lifecycle?
✅ It helps you hook logic at the right phase (e.g., environment setup, bean post-processing).
✅ You can write cleaner startup and shutdown code.
✅ You gain insight into Spring Boot internals, making debugging easier.
📝 Final Thoughts
👉 Understanding these stages is essential for creating robust and maintainable Spring Boot applications.
👉 Next time you build a Spring Boot app, think about where your code fits into this lifecycle!
💬 What lifecycle stage do you hook into most often? Let me know in the comments!
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