He didn't successfully disable Java because Minecraft is built on Java.
It's like if you uninstall Flash or never installed flash and you wanted to play a flash game, it doesn't work.
You still have JAVA running on your machine for minecraft to be running without a hitch.
I found this cd image that supposedly runs the game and java in a portable way, but still relise on Java to run, just doesn't need for it to be installed on the computer.
Seems like it uses a portable JAVA it calls from the internet.
I feel like that's more risky then just running java though.