Your question is still rather broad. it's kind of like saying "I want to build things. What do I need to learn?" The answer would depend on whether you want to build a road, a skyscraper, a bridge, or a guitar.
a game like tic-tac-toe can be done with nothing more than println statement. some games could be done using simple swing components. if you're doing a MMORPG, you need to know about clients, servers, networking, graphics, inter-process communications, and probably a million other things I can't think of.
Could you narrow the scope of your question at all?
and what Maneesh was trying to point out to you is that a
thread with the title "game" in a forum DEVOTED to game development isn't very useful. MANY folks will see your title and decide not to bother reading the body. It looks like you put no effort into your post. If you didn't, why should they?
I'm not saying that is right or wrong, it's just how it is.