Snes Emulator... no. Flash anything w/ no gamepad yes! Games played in web browser w/ gamepad yes!
Java no. You can rip game files already purchased and give them to others but its illegal.
There is no reason you could not have a flash snes emulator but nothing over 5Mb plays quickly, and no game pad. Thats why I dont have a game pad I play flash games on my phone all the time but only touch screen games work. Explore the flash games you can play and want not what you can not have, which is free games that use the game pad(Illegal).
http://www.nintendo-hacks.com/duck_hunt.swf There are alot more flash games but give this one a try on your phone. just go to the site and hit play. works better in portrait mode.