The correct configuration of the shade plugin in my opinion is:
<configuration>
<createDependencyReducedPom>true</createDependencyReducedPom>
<promoteTransitiveDependencies>true</promoteTransitiveDependencies>
...
This creates a consolidated artifact with all the classes of the first level dependencies and declares in the POM of that artifact the second level dependencies.
When issuing maven install the dependency reduced POM is copied in the local maven repository:
...
[INFO] --- maven-install-plugin:2.5.2:install (default-install) @ okapi-lib ---
[INFO] Installing C:\Users\a.falappa\IdeaProjects\okapiframework\okapi\deployment\okapi-framework-sdk\target\okapi-lib-1.42.0-SNAPSHOT.jar to C:\Users\a.falappa\.m2\repository\net\sf\okapi\okapi-lib\1.42.0-SNAPSHOT\okapi-lib-1.42.0-SNAPSHOT.jar
[INFO] Installing C:\Users\a.falappa\IdeaProjects\okapiframework\okapi\deployment\okapi-framework-sdk\dependency-reduced-pom.xml to C:\Users\a.falappa\.m2\repository\net\sf\okapi\okapi-lib\1.42.0-SNAPSHOT\okapi-lib-1.42.0-SNAPSHOT.pom
[INFO] Installing C:\Users\a.falappa\IdeaProjects\okapiframework\okapi\deployment\okapi-framework-sdk\target\okapi-lib-1.42.0-SNAPSHOT-tests.jar to C:\Users\a.falappa\.m2\repository\net\sf\okapi\okapi-lib\1.42.0-SNAPSHOT\okapi-lib-1.42.0-SNAPSHOT-tests.jar
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
...
I have opened a PR to fix this before the next release.
Regards