How to make a bridge between Python and Java programs?

Question

Python

Does anyone have an example of how you can call functions with return parameters of a python program directly from Java? Or, as a last resort, on the contrary - from the python to send values ​​​​to the Java functions?
It is necessary to use libraries like sklearn and keras so that the results of the algorithms are ultimately in Java.
So far, I have only found Jython, but I'm not sure if it will suit this task exactly, maybe there are better solutions. In general, it is interested in something that definitely "works"))

Answer 1

use RPC
use jython (but won't use python3)
run python as a process and read output
run python as a process and store in storage available to all components

Answer 2

Why not use the option of storing the results of Python work in some kind of storage in RAM?
For example Redis or Mongo (in In-Memory Storage Engine mode).