I use Icedtea (gave up on Java - terrible Linux assistance)
Not sure why it won't work for you, I'm using Debian x64, so...
you sure you went to http://technomagic.net/mods/realism ?
Not the texture pack, 8BitMMO using Icedtea
What problems are you having with the Oracle JRE?
In Debian/*buntu/Linux Mint it's just a PPA.