I've got this problem on debian 8.0 after some java update.
(only the welcome screen was shown for a few seconds and then it closed silently)
After some unsuccessfull tweaking with strace and similar I found
../
...
startup.properties
file in the application directory (for me it was /home/jirka/bin/FreeRapid-0.9u4/startup.properties, but you will probably have it wherever you've installed it) and there is commented --debug switch in it (on line 10).
...
#--------------------------------------------------------------------------
# Enable debug mode - advanced logging
#--------------------------------------------------------------------------
#--debug
...
After uncommenting it and restarting the application (from terminal emulator / command line, so I could see the debug output) it turned out that there was some zombie instance of FRD running on background and the new one I tried to launch failed with
9:11:42 PM INFO: Application is already running. Exiting
message.
So after killing the zombie instance everything worked again.