If we define the annotation @SpringBootApplication, the compiler marks the main class as Spring Boot Configuration Class and does all auto configurations and other related services required for SpringBoot.
Generally, @SpringBootApplication is equivalent with three other annotations namely @Configuration, @EnableAutoConfiguration, and @ComponentScan
@Configuration– Used to enable Java-based configuration-
@ComponentScan– Used to enable component scanning. -
@EnableAutoConfiguration– Used to enable Auto-configuration feature of Spring Boot.
So what are the main differences between these Annotations?
@Configuration :
If a class is mentioned with @Configuration annotation, it informs the spring container like the class contains one or more @bean methods, these beans will be processed as bean definition during runtime.
com.java
@Configuration
public class MyBeanConfig {
@Bean(name="demoService")
public DemoClass service()
{
}
}
@ComponentScan :
Scans all the annotated Components available in the entire application. Do the complete Scanning across the project based on the defined dependencies and imports the classes into beans.
@ComponentScan scan detect and register the beans with the classes annotated with @Component, @controller, @service, @Configuration.
@EnableAutoConfiguration :
EnableAutoConfiguration annotation enables all the necessary configurations required for your application configured in your dependencies.
Before Spring Boot 1.2, To implement the Spring Boot, we need to configure these 3 annotations as the basic setup for the application, Since the comfortable use above 3 configurations in the application, From Spring Boot 1.2, The Annotation named @SpringBootApplication introduces and takes care of all the configurations and parameters required for the Main Class.
Below is the Configuration Example to define @SpringBootApplication
package com.example.common;
@SpringBootApplication
public class LocalApplication {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
Conclusion :
Well, Thats end of the @SpringBootApplication annotation, Read more related topics provided below.