How to create Executeable war/jar for Spring boot Multi-Module project

Question

I'm trying to create a uber jar from spring boot multi module project. Example provided https://spring.io/guides/gs/multi-module/

I've two modules:

  <modules>
    <module>library</module>
    <module>application</module>
</modules>

If I run "mvn clean install spring-boot:repackage" from "application" I see that application-0.0.1-SNAPSHOT.war gets created. But once I open that war by 7-zip, I see there's nothing for the "Library" module under the WEB-INF folder. And apprantely, the generated war file doesn't work; 'cause it doesn't have any reference classes from "Library" Here's is the parent pom:

   <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>multiModule</groupId>
  <artifactId>parent-multi-module</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>pom</packaging>
  <modules>
    <module>library</module>
    <module>application</module>
</modules>
<properties>
    <start-class>bismillah.application.DemoApplication</start-class>
</properties>
<repositories>
    <repository>
        <id>spring-releases</id>
        <url>https://repo.spring.io/libs-release</url>
    </repository>
</repositories>
<pluginRepositories>
    <pluginRepository>
        <id>spring-releases</id>
        <url>https://repo.spring.io/libs-release</url>
    </pluginRepository>
</pluginRepositories>

</project>

And finally the pom from "library" module:

    <?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.8.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>bismillah</groupId>
    <artifactId>library</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>library</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

</project>

And finally the pm from "application" module:

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.8.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>bismillah</groupId>
    <artifactId>application</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>application</name>
    <packaging>war</packaging>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <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>
        <dependency>
            <groupId>bismillah</groupId>
            <artifactId>library</artifactId>
            <version>${project.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <executions>
                    <execution>
                      <goals>
                        <goal>repackage</goal>
                      </goals>
                    </execution>
                  </executions>
            </plugin>
        </plugins>
    </build>
</project>

As you can see that I've used "repackage" goal from "spring-boot-maven-plugin"; but still not working. Not sure what am I doing wrong... Can you please help.

Answer 1

Try adding the library module as a dependency of the application module pom in the section