Across linux, MAC, and Windows, is there any way to make a Java program startup on login? I know on windows their would just need to be a shortcut to the jar file in the user's startup folder. But for linux and MAC what should i do?
There's no cross-platform method of starting a program at login or boot, but you can configure each individually.
Windows - Put the program in your user's startup folder in or use a scheduled task, both detailed here: [Instructions]
Mac - Configure through system preferences: [Instructions]
Linux - Configure ~/.bashrc to start on login or use /etc/rc.d/rc.sysinit to start on boot.