Please take a look at this image: http://i.imgur.com/pHIg1AA.png Is it possible to change the application name (\"My JavaFX-based Mac App\") in the Mac OS X system menu bar
That should work as is always worked for me :D
primaryStage.setTitle("LOLOLOLOL");
This changes your window's name. You can change this value at any time, if you have the Stage element at your disposal.
Stage