<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-jar-plugin</artifactId>
  <version>3.0.0</version>
  <configuration>
    <archive>
      <manifest>
        <addClasspath>true</addClasspath>
        <classpathPrefix>lib/</classpathPrefix>
      </manifest>
    </archive>
  </configuration>
</plugin>

Class-Path: lib/commons-logging/commons-logging/1.1.1/commons-logging-1.1.1.jar lib/com/google/code/gson/gson/2.8.2/gson-2.8.2.jar

Class-Path: lib/commons-logging-1.1.1.jar lib/gson-2.8.2.jar

<classpathLayoutType>simple</classpathLayoutType>

<classpathLayoutType>custom</classpathLayoutType>
<customClasspathLayout>lib/$${artifact.artifactId}-$${artifact.version}$${dashClassifier?}.$${artifact.extension}</customClasspathLayout>