I recently dusted off an old project of mine, a java based arcade emulator called 'CottAGE'. I updated so that it will do it's rendering using OpenGL (using the LWJGL library) and enabled it for Java Web Start.
Could you please give it a try? (You need java 1.4 or higher installed and you need a half decent video card with openGL support).
I'm wondering if the openGL code will work for everybody. It should work with windows, linux and mac (although mac will suffer from disabled input, due to an LWJGL bug).

Black Tiger: http://www.movegaga.nl/80s/jemu_blktiger.php
Space Invaders: http://www.movegaga.nl/80s/jemu_invaders.php
Galaga: http://www.movegaga.nl/80s/jemu_galaga.php
Solomon's Key: http://www.movegaga.nl/80s/jemu_solomon.php
1943 kai (http://www.movegaga.nl/80s/jemu_1943kai.php)
Ms.Pacman (http://www.movegaga.nl/80s/jemu_mspacman.php).

Thanks :-)