5- @SpringBootApplication annotation

 

@SpringBootApplication internally contains 

-->   @SpringBootConfiguration 

-->   @EnableAutoConfiguration

-->   @ComponentScan

@SpringBootConfiguration internally uses @Configuration which is a java based configuration.

There are three types of configuration

1- xml based configuration

2- java based configuration

3- annotation based configuration

@EnableAutoConfiguration-  If spring-starter-web dependency exists then enables dispatcher 

servlet  to EnableAutoConfiguration classes.

@ComponentScan-  to scan spring components in particular package

                                 -->  basically scan base and subpackages

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