Jython is however stuck with Python 2.x compatibility only as far as I know (I'd be happy to be proven wrong).
Re:A Python Interpreter Written in Rust
by mooreds on Saturday February 02, 2019 @02:17PM
(#19065002)
Jython 3.x development is "in progress":
https://wiki.python.org/jython/JythonFaq/GeneralInfo
Last commit was over a year ago:
Jython, as you state, does not: http://www.jython.org/jythonbook/en/1.0/Concurrency.html