Answer by DougW for GUI objects not showing in Java on Mac

I could be wrong--been a long time since I've done a GUI in java--but I'm guessing your issue is making the JFrame visible before you finish adding elements. I think you need to either do that afterwards, or call update on the frame.

EDIT - Also, not sure setting the layout to null is a good idea. I've always used GridBag, but it might lose its default if you set it to null.