Hi Liviu,
It nice to hear from you. At the moment CDT is still, and for the foreseeable future, built with Java 8, as is the Eclipse Platform project. Running Eclipse+CDT with newer Javas is supposed to work and any areas there should be swiftly tackled. (Please note that Eclipse+CDT's released prior to 2018-12 are unlikely to "just work" with JDKs newer than Java 8.)
At some point we should discuss when we want to start building CDT with newer Javas. I am open to starting that discussion now, as I am also pleased to review & commit changes to CDT to make sure it builds on newer JDKs. To start off the discussion, I would like to point out that AFAIU if we build with a newer Java, then that is the oldest version we can support.
All that said, FWIW, I just did a "mvn package -DskipDoc" with AdoptOpenJDK 12 on Ubuntu 18.04 and it built fine (doc building did fail, hence -DskipDoc). So perhaps there is something else going on. Send along your error message for more help.
I hope that helps.
PS. Congratulations on the new Mac! I hope I may be able to enlist your help on a few Mac issues going forward. Mac support is important to the CDT community, but at the moment we don't have many people doing there day to day dev work on Mac.
Jonah
