Autowire a Repository to a library project in Spring Boot - spring

Question

I'm working on a Spring Boot multi-module project. I have created separate modules as follows
com.foodshop.api - (this is a Spring Boot project, the starting point and both com.foodshop.application and com.foodshop.persistence are added as dependencies here)
com.foodshop.application - (the application layer where I have the business logic, thi s is a library project and spring-boot-starter and com.foodshop.persistence are added as dependencies here)
com.foodshop.persistence - (this is where the repositories defined, spring-boot-starter-data-mongodb is added as a dependency in this project)
All 3 project mentioned above are wrapped inside a parent pom maven project and the parent pom.xml looks as follows;
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.foodshop</groupId>
<artifactId>foodshop-backend</artifactId>
<version>0.0.1</version>
<packaging>pom</packaging>
<properties>
<maven.compiler.source>11</maven.compiler.source>
<maven.compiler.target>11</maven.compiler.target>
</properties>
<modules>
<module>foodshop.persistence</module>
<module>foodshop.application</module>
<module>foodshop.api</module>
</modules>
</project>
The project builds without any errors. The application class of foodshop.api I have annotated as follows so that it can see the dependencies in other modules
#SpringBootApplication(scanBasePackages = {"com.foodshop"})
But when I try to run the API project, it looks like the foodshop.application fails to find and autowire the repositories defined in foodshop.persistence
I get an error as follows;
***************************
APPLICATION FAILED TO START
***************************
Description:
Parameter 0 of constructor in com.foodshop.application.MealManager required a bean of type 'com.foodshop.persistence.repository.MealRepository' that could not be found.
The injection point has the following annotations:
- #org.springframework.beans.factory.annotation.Autowired(required=true)
Action:
Consider defining a bean of type 'com.foodshop.persistence.repository.MealRepository' in your configuration.
I have properly annotated MealRepository with the #Repository annotation but I feel like I have missed something important.
It would be very much appreciated if I can get some help on this issue.

Answer 1

After more than 20 hours reading and following the trial and error approach, I was able to identify the issue. As per the Spring official documentations
If your application also uses JPA or Spring Data, the #EntityScan and
#EnableJpaRepositories (and related) annotations inherit only their
base package from #SpringBootApplication when not explicitly
specified. That is, once you specify scanBasePackageClasses or
scanBasePackages, you might also have to also explicitly use
#EntityScan and #EnableJpaRepositories with their package scans
explicitly configured.
Since I use spring-boot-starter-data-mongodb, I annotated my Application class as follows;
#SpringBootApplication(scanBasePackages = {"com.foodshop"})
#EnableMongoRepositories(basePackages = "com.foodshop.persistence")
public class Application {
// main method goes here.
}
#EnableMongoRepositories annotation did the trick.