如何在mac上使用netbeans更改java应用程序的默认图标?

I have a java application that will need to be deployed on both windows and mac. On windows, I've configured the system to use a .png file as the icon for the application, but the mac requires an icns file. I've created the icns file, but I can't figure out how to set that as the icon to use for the application (in the dock, expose, etc). I'd also need the PC side to ignore that icon assignment.I have a java application that will need to be