Mastering Spring Boot: Key Annotations You Should Know

Spring Boot is a framework built on top of the Spring Framework that simplifies the development of Java applications by providing a set of powerful annotations. These annotations reduce boilerplate code and configure the application in a more declarative way. In this article, we’ll explore some of the most commonly used annotations in Spring Boot, providing detailed explanations and examples.

1. @SpringBootApplication

The @SpringBootApplication annotation is the core annotation used to mark the main class of a Spring Boot application. It encapsulates three key annotations:

• @Configuration: Marks the class as a source of bean definitions.
• @EnableAutoConfiguration: Tells Spring Boot to start adding beans based on classpath settings, other beans, and various property settings.
• @ComponentScan: Tells Spring to scan the package for components, configurations, and services.

This annotation is typically placed on the main class, the one that contains the main method.

Example:

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class DemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}