'if you dont know what it means why the hell are you using it...' Geekspeak at its worse...
Well, unfortunately, that's the very point with Java ....
If you were using a website that required you to run a java applet, you'd probably know about it.
If you were using a locally installed java software application.... you'd probably already know about it.
Hence .... if you don't know what it is or what you need it for, you are unlikely to have any use for it.
Uninstalling Java won't do you any harm. If you find some software or website breaks after you've uninstalled it, you can easily reinstall it.