I am wondering if it is possible to call python functions from java code using jython, or is it only for calling java code from python?
This gives a pretty good overview over the current options. Some of which are named in other answers. Jython is not usable until they decide to implement Python 3.x and many of the other projects are coming form the python side and want to access java. But there are a few options still, to name something which has not been named yet: gRPC