I noticed that jbdevstudio.ini on osx app says:

eclipse.product=org.eclipse.epp.package.jee.product

it also lists several lines multiple times (showsplash, product and permgen).

Note, I used the updatesite into a normal eclipse - but don't think that should affect this.

Here is how my file looks like:

-startup
../../../plugins/org.eclipse.equinox.launcher_1.1.0.v20100507.jar
--launcher.library
../../../plugins/org.eclipse.equinox.launcher.cocoa.macosx_1.1.1.R36x_v20100810
-product
org.eclipse.epp.package.jee.product
--launcher.defaultAction
openFile
-showsplash
org.eclipse.platform
--launcher.XXMaxPermSize
256m
--launcher.defaultAction
openFile
-showsplash
org.eclipse.platform
--launcher.XXMaxPermSize
256m
--launcher.defaultAction
openFile
--launcher.XXMaxPermSize
256m
--launcher.defaultAction
openFile
-vmargs
-Dosgi.requiredJavaVersion=1.5
-XstartOnFirstThread
-Dorg.eclipse.swt.internal.carbon.smallFonts
-XX:MaxPermSize=256m
-Xdock:icon=../Resources/Eclipse.icns
-XstartOnFirstThread
-Dorg.eclipse.swt.internal.carbon.smallFonts
-Xdock:icon=../Resources/Eclipse.icns
-XstartOnFirstThread
-Dorg.eclipse.swt.internal.carbon.smallFonts
-Xms512m
-Xmx1024m
-Dosgi.bundles=reference:file:org.eclipse.equinox.simpleconfigurator_1.0.200.v20100503.jar@1:start
-Dosgi.instance.area.default=@user.home/workspace
-XstartOnFirstThread
-Dorg.eclipse.swt.internal.carbon.smallFonts
-Xdock:icon=../Resources/JBDevStudio.icns