How is the application initialization sequence carried out when starting Spring Boot?

When launching a Spring Boot application, it goes through several initialization stages:

1. Starting the main() method — SpringApplication.run() is called, which initiates the process.
2. Creating the application context — an ApplicationContext is created, usually AnnotationConfigApplicationContext or SpringApplicationContext.
3. Component scanning — Spring scans classes with annotations (@Component, @Service, @Repository, @Controller) and registers beans.
4. Automatic configuration — thanks to @EnableAutoConfiguration, Spring Boot automatically configures components based on dependencies and settings.
5. Bean initialization — all beans are created and initialized, and methods with @PostConstruct annotations are called.
6. Starting the embedded server (e.g., Tomcat) — if it's a web application, the embedded server is started.
7. Calling ApplicationReadyEvent — signals that the application is ready to operate.

Thus, Spring Boot simplifies application startup by automatically configuring the environment and components.