NetBeans

You could be missing curly brackets, you could not have net beans set up properly with a JDK; If you copied the class and you pasted it in a file that was not named Solution then that would create a problem. If you copied the whole entire code then that name/file would still be a problem and, as Thomas mentioned, the package information would also be incorrect. There could be other problems but without more information we won't be able to do more than speculate.

It seems to be the new normal that no one thanks you for help anymore... but yes, you're of course right. I was not very elaborate with my explanation, but that was because I got zero feedback on my last posts. I will probably leave that to the more motivated ;)