[rrd4j] Trying to build a .jar, failing

I’m trying to build a custom rrd4j.jar in order to have a tool that can pull data from a ( non- rrd4j ) persistence into rrd4j.
The code works from within the IDE (VSC), however creating a .jar fails. Did one of the devs succeed in creating a .jar with the code from github ( version 3.3.1 or even the master 3.8)?

Solved it by creating the .jar only (without all the testing) .
Used a command like: & mvn jar:jar -f "d:\RRD4J\rrd4j-3.3.1\pom.xml" which was created by VSC by using the Maven tab (lower left corner!) sub-tab rrd4j – jar.