Hi, I did excatly what is posted, with the j2sdk file and i can not get it to install right,

when i type: java -version
I get not a vaild command
when i type: which java
I get a no java in .........................

So what am i doing wrong? I have tried to re-install the file but it keeps saying that the file (j2sdk) is already installed?

Window user getting really mad a linux.

thanks
Daryl