Disapearing code O_O

I keep writing up code files with Java. I'm making a game for a class I'm in, and every time I restart the computer AFTER SAVING, the code file deletes all the text in it. Netbeans says it has invalid characters, so I think it changed all my code to a blankpost character....

T_T how do I get it back i needs it? and what is wrong? how do i fix it?

Thanks

>>1
lern 2 git commit

Sorry, that was completely unhelpful. But I have no idea how you expect us to help anyway. If I had to hazard a guess, I'd say your assignment is probably to modify a pre-existing source file which you downloaded from your class website, and you just edited it directly in Temporary Internet Files. Reboot the computer, poof, it's gone. Netbeans probably just gives you a blank file, because your file is gone.

Save shit to a proper place on your drive first. Also, /prog/ is not your tutor.