Wow. It works.
I went easier (? 
) route and put 2.7.0 jar, not using bundle. I found your support very helpfull, thank you!
It wasnt so easy to enable it, due tu multiple information, which seemed to me (not having experience with java in general) contradictory.
For example in bundle approach if I may suggest two things to correct in your top post ([beta testers wanted!] Jython addon w/ helper libraries (requires OH 2.5.x)):
- add section, what is NOT needed:
a. no need to instal NGRE (or if needed put it as a step) -> this is something which make me resign trying bundle, as I did not understand it
b. no need to change /etc/default/openhab2 EXTRA_JAVA_OPTS (this was asked multiple times by oldtimers in the long thread, but its missing from top post) - explain in more clarity sentence “The jar contains the core and community helper libraries, so there’s no need to copy them from the repo. However, the core scripts will need to be copied to /automation/jsr223/python/core/.” - I still do not understand difference in ‘core helper libraries’
vs ‘core scripts’. Documenting it a bit longer would be helpful, especially if do not know if this step is needed or not, and what exactly is needed. I would separate here things MUST to do (to put in first list), with the things NOT needed to do (like 1a 1b above).
Once again, thank you kindly for your work @5iver, I appreciate it!