'Field required a bean of type that could not be found.' error spring restful API using mongodb

Solved it. So by default, all packages that falls under @SpringBootApplication declaration will be scanned.

Assuming my main class ExampleApplication that has @SpringBootApplication declaration is declared inside com.example.something, then all components that falls under com.example.something is scanned while com.example.applicant will not be scanned.

So, there are two ways to do it based on this question. Use

@SpringBootApplication(scanBasePackages={
"com.example.something", "com.example.application"})

That way, the application will scan all the specified components, but I think what if the scale were getting bigger ?

So I use the second approach, by restructuring my packages and it worked ! Now my packages structure became like this.

src/
├── main/
│   └── java/
|       ├── com.example/
|       |   └── Application.java
|       ├── com.example.model/
|       |   └── User.java
|       ├── com.example.controller/
|       |   ├── IndexController.java
|       |   └── UsersController.java
|       └── com.example.service/
|           └── UserService.java
└── resources/
    └── application.properties

Add the @Service in the service/UserService.java.

I also had the same error:

***************************
APPLICATION FAILED TO START
***************************

Description:

Field repository in com.kalsym.next.gen.campaign.controller.CampaignController required a bean of type 'com.kalsym.next.gen.campaign.data.CustomerRepository' that could not be found.


Action:

Consider defining a bean of type 'com.kalsym.next.gen.campaign.data.CustomerRepository' in your configuration.de here

And my packages were constructed in the same way as mentioned in the accepted answer. I fixed my issue by adding EnableMongoRepositories annotation in the main class like this:

@SpringBootApplication
@EnableMongoRepositories(basePackageClasses = CustomerRepository.class)
public class CampaignAPI {

    public static void main(String[] args) {
        SpringApplication.run(CampaignAPI.class, args);
    }
}

If you need to add multiple don't forget the curly braces:

@EnableMongoRepositories(basePackageClasses
    = {
        MSASMSRepository.class, APartyMappingRepository.class
    })