The problem you are facing is that when upstart (or systemd, or the scripts in /etc/rc.d/) are run, there is normally no graphic service ("the X server") running.

Moreover, the availability of the graphic subsystem in Unix is strictly bond to the concept that a user has done a graphic login, and just this user has the right to use the graphic environment. It is customary NOT to start a graphic subsytem for root --- and the upstart scripts are run by root.

To automatically start a graphic application at the start of the system, my approach would be:

1. create a user for this purpose. Set it up so that its session will autostart.
   
   




2. set up a startup application for this user with the program you want; choose "startup application" in the dash:
   




3. for restarting the application when it exits/crashes, you can simply embed it in a script:

   
   
   

        #!/bin/bash
   
        #
   
        while true; do 
   
             /full/path/to/start_myapp.sh    # NO background (&)!
   
             # if we land here it exited
   
             sleep 5
   
        done
   
   

If you use this script, it is really important that the command start_myapp.sh should not launch the application in background. Otherwise, more complex strategies are required to auto-restart...

Notice that you can use your normal user in parallel too; just choose "switch user" from the panel (adapt to your flavor of Ubuntu) and you will have another graphical login screen; you can switch back-an-forth using CTRL-ALT-F7 and CTRL-ALT-F8...