🧩 How Spring Boot Wires Everything Automatically — The Container Explained

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How Spring Container Works Behind the Scenes

If you’ve built even a single application with Spring or Spring Boot, you’ve already been using the Spring container — even if you didn’t realize it.

You’ve annotated your classes with @Service, @Repository, or @Component, and magically, they were created, injected, and managed without any manual new calls.

But what exactly is this “Spring container”? And what happens under the hood when your application starts?

In this article, we’ll break down exactly how the Spring container works behind the scenes — from classpath scanning to bean creation, dependency injection, and lifecycle management.

First: What Is the Spring Container?

The Spring container is the core part of the Spring Framework that manages the lifecycle and configuration of application beans.

It is responsible for:

• Creating objects (beans)
• Injecting dependencies
• Managing bean scopes…