I was able to also create an .app file with install4j for running Spark on my Mac. The rest of the office uses Windows, so it is just me on the Mac.
I noticed that when previously using Spark for OS X, when a new message would arrive, the icon in the dock would bounce along with a number added to it. I had replaced the message.icns file in src\resource\image directory because I realized it would load the Spark icon instead of the desired icon.
With this icon in place, the dock jcon no longer bounces on a new message. Does anyone have any tips on how to get that work again?