I wrote a Java server that blocks spam based on my criteria and set it to run like this:

http://manpages.ubuntu.com/manpages/trusty/man8/update-rc.d....

I didn't do any daemonzing like we used to do in the C days so I'm not sure that the systemd approach mentioned in the article does it better (not against the idea, maybe it's needed on non-Ubuntu systems?).

I just needed to write a simple shell script with the basics and this:

...

  case "$1" in
      start)
          startup
      ;;
      stop)
          shutdown
      ;;
      restart)
          restartit
      ;;
  esac

...