Configuration using annotation @SpringBootApplication

The Spring Boot documentation for @SpringBootApplication states

Many Spring Boot developers always have their main class annotated with @Configuration, @EnableAutoConfiguration and @ComponentScan. Since these annotations are so frequently used together (especially if you follow the best practices above), Spring Boot provides a convenient @SpringBootApplication alternative.

The @SpringBootApplication annotation is equivalent to using @Configuration, @EnableAutoConfiguration and @ComponentScan with their default attributes: [...]

where the @ComponentScan javadoc states

If specific packages are not defined, scanning will occur from the package of the class that declares this annotation.

That is, only the types that are in the same package as your ReadingListApplication will be scanned.

If you want a custom configuration, provide your own @Configuration, @EnableAutoConfiguration, and @ComponentScan, as appropriate.

When setting up a Spring boot project, have your Application class (the one that contains the @SpringBootApplication annotation in the base package.

One of the things the @SpringBootApplication does is a component scan. But, it only scans on sub-packages. i.e. if you put that class in com.mypackage, then it will scan for all classes in sub-packages i.e. com.mypackage.*.

If you do not want to do it this way, you can also add a @ComponentScan to a class specifying the root package i.e @ComponentScan("com.mypackage")

I would recommend you have a base package i.e com.mypackage. And within those packages, have your sub-packages. Have you class containing the @SpringBootApplication in that base package.

I was having the same problem and to solve it I renamed my packages like this.

"com.project"

there you can place your SpringBootAplication main class, then just create the others packages beginning with "com.project"

"com.project.dao"

"com.project.controller"

Creating this sub project structure you have no need to use scanBasePackages in @SpringBootApplication annotation, doing this your main class will be able to find every component in your project.

And in case you chose to use scanBasePackages remember that you need to set all your components packages like this.

@SpringBootApplication(scanBasePackages = {"com.project.dao", "com.project.controller"})

Checking the Spring documentation:

http://docs.spring.io/spring-boot/docs/current/api/org/springframework/boot/autoconfigure/SpringBootApplication.html

You can override, with the @SpringBootApplication, the default values of component scan. You just need to include it as a parameters:

@SpringBootApplication(scanBasePackages = "entertainment")

or String array:

@SpringBootApplication(scanBasePackages = {"entertainment", "readinglist"})