Hey,I kind of did a work around. I found this on another forum:
I also searched for days without success but then, I got it to work quite simply.

In Raspian click Menu,Preferences,Main Menu Editor
Click Preferences and check Default applications for LXSession
Click OK and close main menu editor
Now click Menu and Under Preferences click on Default applications for LXSession
LXSession configuration opens
Click Autostart
Under Manual autostarted applications paste in your java command line
click add
close the LXSession configuration application and reboot your pi
your java app should run after reboot

Hey,yes, I go to that same exact directory,but the file isn’t there. And yes I can load MM with pm2 start mm.sh. That’s what so weird about the whole thing. It’s as if the file doesn’t exist but yet the program is working somehow.

@eugekiller

Hey,I’m having this exact same issue. I’m trying to follow your steps but I can’t locate the pm2-init.sh file. I have the pm2 installed. I go follow the same directory paths as stated but that one file isn’t there. Any ideas about where the file is? It has to exist somewhere since I’m able to use it.