You can try using launch() or exec(). I have attached other posts that are relevant.
Kf
- https://processing.org/reference/launch_.html
- https://stackoverflow.com/questions/13991007/execute-external-program-in-java
- https://forum.processing.org/two/discussion/20568/how-do-i-launch-a-compiled-sketch-from-within-another-sketch
- https://forum.processing.org/two/discussion/26485/launch-won-t-launch-my-compiled-processing-sketch
- How do i get the output of a command?