I use several school computers, that have different operating systems. To make sure that I always have my tools available, I like to install a lot of programs to my "roving profile". This is possible with the Java SDK on every OS that isn't Microsoft Windows 2000 or XP or later.
The reason is that, despite owning the folder I'd like to install to and having full permissions on the executable, Java just flat out won't install unless I'm an administrative user. I'd like to know why. It's really inconvenient having to putty into myself just to be able to use the java compiler when I'm doing my homework.
I was also wondering if the convenient workaround I've thought of that I have not tried, simply grabbing a windows computer on my own, installing J2SDK onto that computer, and copying the folder over, would work. I suspect it might, given that Java consists mostly of pre-compiled binaries that have to work the same way on every windows system, but I figured I'd see what other people thought.
Mostly, though, this just seems like such an odd restriction. In any other operating system, any similar "you must be root" nonsense can be quickly and easily bypassed. It's always puzzled me as to why the computer you're sitting on wants to force you to be someone who can easily damage your system, the one user you can't sandbox and do any pre-emptive damage control with, before it starts tossing grenades your way. I never build or install anything as a privileged user unless I absolutely have to; it's really bizarre that Sun actually /enforces/ a bad security practice this way.