jar文件的Mac OS java版本问题

I have already developed a setup.exe for windows, having features like autodetecting JRE version, autoinstalling required JRE version, autostart on windows start etc. I have made this exe from a jar file(jar file was not having the above mentioned features. Features are added later when transforming a JAR to EXE. Now I was wondering if I can somehow convert exe to DMG, APP or JAR or I can add the above mentioned features in my JAR file only.) By default Mac comes with Java version 5 and my application needs minimum Java version 6 to runI have already developed a setup.exe for window