What must I learn to make such games? Example like c++? Java?? Or what must I learn?
Jumping right into C++ wont be very smart.
Start with some easy shit like VB.
Maybe some HTML for web sites if you have no prior experience with coding.
Once you get a grasp of how most coding works, other languages become easier to work with.
But to answer your question, I would recommend jumping into some beginner platforms of game development first.
Here are a few off the top of my head:
Game Creator
Scrria
Game Maker Studio
Cry Engine 3
chocolate_1995 (12-30-2012),Ticherhaz (08-15-2013)
Okay this might seem harsh but you need to take as much criticism as you can before you learn a language.
A: Making a whole FPS MMO like Combat arms for example is phsyically, and mentally "impossible" for one human. People don't understand that companies that make WoW, Combat Arms, CS:S, CoD series etc. Have THOUSANDS working to make one game, and even with thousands they take YEARS to make. YEARS for THOUSANDS of people. You are not going to make a 3d FPS as successful as combat arms with out it having huge bug issues, horrible anti cheat, horrible graphics, etc. you are going to be lacking in some area.
B: If you have this high of goals to make a game that is impossible as explained above, your going to kill your hopes cause I used to be like you before I learned a language, thought it was easy I can do it, right? my mom said i can do anything I put my mind to. Wrong, you will learn the hard way by either A) copying peoples codes on tutorials and not realizing how ahead you are of yourself or B) just giving up early stages cause you don't want to deal with learning what a compiler does when all you want is a game.
C: C++ is the market standard right now (C# coming along) as it can be dual platform (so can java). But java's game engines are as "extensive" as c++ or c#.
Again sorry if the criticism seemed harsh but it's the truth, someone has to tell you.
actually... you are wrong at the A: part... im game developer and the thing you said about Thousands of people working on one game for years is just a myth... if youre good coder and you have passionate small team you can make something great and big and hopefully unique with 1-4 years or just keep working on it...