Spring Boot 3 Crash Course Part 2: Spring Into The Core

In the last part, we learned about the concepts of dependency injection and inversion of control (Part 1 Link). This part is going to be a deep dive into the Spring Core framework itself and understanding various annotations.

Edit: Part 3 is now available. Link

Quick Summary Of Last Part:

In Dependency Injection, instead of a component creating its own dependencies or objects it relies on, these dependencies are provided or “injected” from the outside. This decouples components and makes it easier to replace or modify individual parts of the system without affecting the entire application.

In traditional programming, the application controls the flow by calling various functions and methods. In IoC, the control over certain aspects of the application is shifted to a container or framework, which manages the creation and lifecycles of objects and their dependencies. DI is one of the mechanisms often used to implement IoC.

But how do we do this in code?

Before we start, Go ahead and create a new Spring Boot project just like we did in the last part from https://start.spring.io/ and open it in your IDE/Editor.