How to Create an Additional Attached JAR Artifact

Add <includes>/<include> or <excludes>/<exclude> in your pom.xml. Add a classifier as well.

Note: Define the JAR Plugin in a new execution. Otherwise, it replaces the default use of the JAR Plugin. It does not add a second artifact. The classifier is also required to create more than one artifact.

<project>
  ...
  <build>
    <plugins>
      ...
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-jar-plugin</artifactId>
        <version>4.0.0-beta-2</version>
        <executions>
          <execution>
            <phase>package</phase>
            <goals>
              <goal>jar</goal>
            </goals>
            <configuration>
              <classifier>client</classifier>
              <includes>
                <include>**/service/*</include>
              </includes>
            </configuration>
          </execution>
        </executions>
      </plugin>
      ...
    </plugins>
  </build>
  ...
</project>