Spring Boot multi (maven) module project can't find its Repository -- how to fix this?

Question

As my first step in mastering Java 9 modules, I'm first creating a Java program that resides in nested directories, all joined by a root-level Maven pom.xml. That is, Java modules aren't yet involved.

The source for my program is a Spring Boot program that already works. I have divided that program into a controller (access Maven module) and data access (persistence Maven module). My tutor for this task has been this Spring site: https://spring.io/guides/gs/multi-module/ .

I'm running this thru Visual Source Code, with Java 11 in my JAVA_HOME. The Spring Boot program starts, then yields this sort of error:

Parameter 0 of constructor in com.logicaltiger.persistence.service.LocationService required a bean of type 'com.logicaltiger.persistence.repository.LocationRepository' that could not be found.

The program worked before I sliced / diced it, so my problem is with Spring configuration.

My request? Can my configuration be fixed so that Spring Boot finds all of its parts?

The AccessApplication has this:

@SpringBootApplication(scanBasePackages = "com.logicaltiger")
@ComponentScan("com.logicaltiger")
@EnableAutoConfiguration
public class AccessApplication {

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

}

LocationService has this:

@Service
[snip]

private final LocationRepository locationRepository;

public LocationService(LocationRepository locationRepository) {
    this.locationRepository = locationRepository;
}

LocationRepository has this:

@Repository
public interface LocationRepository extends CrudRepository<Location, Long> {

This is my directory structure, ignoring.mvn, etc.

district-updater-modules
    access
        src
            main
                java
                    com
                        logicaltiger
                            access
                                controller
                                    (various controller files, with @Controller annotation)
                                util
                                     Utilities.java
                                AccessApplication.java
                resources
                    static
                    templates
                    application.properties
        pom.xml
    persistence
            main
                java
                    com
                        logicaltiger
                            persistence
                                model
                                    (various model files)
                                repository
                                    LocationRepository.java
                                service
                                    LocationService.java
                                util
                                     Utilities.java
                                AccessApplication.java
                resources
        pom.xml
    pom.xml

The root pom.xml:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" [snip] >
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.logicaltiger</groupId>
    <artifactId>district-updater-modules</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>district-updater-modules</name>
    <description>Wrapper for the modules of DistrictUpdater -- Java modules</description>
    <packaging>pom</packaging>

    <modules>
        <module>access</module>
        <module>persistence</module>
    </modules>

</project>

The access pom.xml (some dependencies omitted):

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" [snip] >
    <modelVersion>4.0.0</modelVersion>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.4.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.logicaltiger.access</groupId>
    <artifactId>access</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>district-updater-modules-access</name>
    <description>DistrictUpdater web API access module</description>
    <packaging>jar</packaging>

    <dependencies>
        <dependency>
            <groupId>com.logicaltiger</groupId>
            <artifactId>persistence</artifactId>
            <version>${project.version}</version>
        </dependency>    
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

The persistence pom.xml (some dependencies omitted):

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" [snip] >
    <modelVersion>4.0.0</modelVersion>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.4.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.logicaltiger</groupId>
    <artifactId>persistence</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>district-updater-modules-persistence</name>
    <description>DistrictUpdater persistence module</description>
    <packaging>jar</packaging>

    <properties>
        <java.version>11</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
    </dependencies>

</project>

Thanks,

Jerome.

Answer 1

After a lot of surfing and experimenting, I finally found the solution here .

In addition to @ComponentScan("com.logicaltiger") you also need

• @EnableJpaRepositories(basePackages = "com.logicaltiger") in order to find all repositories,
• and also @EntityScan("com.logicaltiger.*") in order to find all entities.

Hence:

@SpringBootApplication(scanBasePackages = "com.logicaltiger")
@ComponentScan("com.logicaltiger")
@EnableJpaRepositories(basePackages = "com.logicaltiger")
@EntityScan("com.logicaltiger.*")
@EnableAutoConfiguration
public class AccessApplication {

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

}