By default, the repackage goal will replace the original artifact with the repackaged one. That's a sane behavior for modules that represent an app but if your module is used as a dependency of another module, you need to provide a classifier for the repackaged one.

The reason for that is that application classes are packaged in BOOT-INF/classes so that the dependent module cannot load a repackaged jar's classes. If that is the case or if you prefer to keep the original artifact and attach the repackaged one with a different classifier, configure the plugin as follows:

<project>
  ...
  <build>
    ...
    <plugins>
      ...
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
        <version>2.1.12.RELEASE</version>
        <executions>
          <execution>
            <id>repackage</id>
            <goals>
              <goal>repackage</goal>
            </goals>
            <configuration>
              <classifier>exec</classifier>
            </configuration>
          </execution>
        </executions>
        ...
      </plugin>
      ...
    </plugins>
    ...
  </build>
  ...
</project>

If you are using `spring-boot-starter-parent`, the `repackage` goal is executed automatically in an execution with id `repackage`. In that setup, only the configuration should be specified as shown in the following example:

<project>
  ...
  <build>
    ...
    <plugins>
      ...
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
        <executions>
          <execution>
            <id>repackage</id>
            <configuration>
              <classifier>exec</classifier>
            </configuration>
          </execution>
        </executions>
        ...
      </plugin>
      ...
    </plugins>
    ...
  </build>
  ...
</project>

This configuration will generate two artifacts: the original one and the repackaged counter part produced by the repackage goal. Both will be installed/deployed transparently.

You can also use the same configuration if you want to repackage a secondary artifact the same way the main artifact is replaced. The following configuration installs/deploys a single task classified artifact with the repackaged app:

<project>
  ...
  <build>
    ...
    <plugins>
      ...
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-jar-plugin</artifactId>
        <version>@maven-jar-plugin.version@</version>
        <executions>
          <execution>
            <goals>
              <goal>jar</goal>
            </goals>
            <phase>package</phase>
            <configuration>
              <classifier>task</classifier>
            </configuration>
          </execution>
        </executions>
    </plugin>
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
        <version>2.1.12.RELEASE</version>
        <executions>
          <execution>
            <id>repackage</id>
            <goals>
              <goal>repackage</goal>
            </goals>
            <configuration>
              <classifier>task</classifier>
            </configuration>
          </execution>
        </executions>
        ...
      </plugin>
      ...
    </plugins>
    ...
  </build>
  ...
</project>

As both the maven-jar-plugin and the spring-boot-maven-plugin runs at the same phase, it is important that the jar plugin is defined first (so that it runs before the repackage goal).

Again, if you are using `spring-boot-starter-parent`, this can be simplified as follows:

<project>
  ...
  <build>
    ...
    <plugins>
      ...
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-jar-plugin</artifactId>
        <executions>
          <execution>
            <id>default-jar</id>
            <configuration>
              <classifier>task</classifier>
            </configuration>
          </execution>
        </executions>
    </plugin>
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
        <executions>
          <execution>
            <id>repackage</id>
            <configuration>
              <classifier>task</classifier>
            </configuration>
          </execution>
        </executions>
        ...
      </plugin>
      ...
    </plugins>
    ...
  </build>
  ...
</project>