In Spring Boot, annotations play a crucial role in defining behavior, configurations, and bean management.


Core Annotations

1. @SpringBootApplication

   - Combines three annotations: `@Configuration`, `@EnableAutoConfiguration`, and `@ComponentScan`.

   - Marks the main class that bootstraps the Spring application.


2. @RestController

   - Combines `@Controller` and `@ResponseBody`.

   - Used for creating RESTful web services. It automatically serializes return objects to JSON or XML.


3. @RequestMapping

   - Maps HTTP requests to handler methods of MVC and REST controllers.

   - Can be applied at both class and method levels.