Well, I have got a "game" with some classes (Frame, Board, Enemy, Bullet, Dude). In Board class, I have got a method, to load a background (ImageIcon i = new ImageIcon ... )And it just work perfectly, but it is just background... (was making the game step by step with tutorial on Youtube. )
I looked at code in David Brackeen's book, but I don't understand it. There are "thousands" of classes, and a lot of them are almost equals. Are all of this even necessarily? Maybe I will understand, if I will buy a book, but for now, there is no money for this.

I need just this, then, moving, collision, enemys and all other stuff are much more easier than this. So, can I please you something? If you know any site, with step by step tutorial, how to make very simple tile based game, can you please post the link of the website here? I was searching the web, but I haven't found tutorial which explain how to create tile based game in java, step by step. Or if you know a site where I can download a source code of a simple tile based game, and than I will probably understand how to make this game. (But it have to work)
Ow, and about error, which I mention some posts above. I was doing something very stupid. My code was a disaster from first to last line

I was laughing to myself.