I've never programmed in java but I don't think that will be the point with my opinion.
It's not smart to pick a 'random' resolution. In C++ the function 'ChangeDisplayMode" returns false at random resolutions that doesn't exist.
When the gamer goes to options he might want to change the resolution. So give him known ones(640*480, 1024*768, 1280*720, etc)
link:
http://en.wikipedia....play_resolution (scroll down a bit)
I mostly use 640*480 to start my projects with. When I create a game I'm trying to get around 1360*768. And then adjust my resolution to a "fullscreen" window for the gamer.
And 3-5 minutes each video? You have written 5 lines of code now so maybe go a little bit faster, or make the video much longer?
~EngineProgrammer