emacs - project explorer and auto complete features - is it available?

Question

I know that Emacs is a very powerful editor out there. I try to use it occasionally and want to learn it better. But to learn it better i have to use it more frequently than I am using now.

But one big obstacle is that I could not find the basic properties like a project auto completion. Maybe I am lazy but I dont want to write again and again the same long method names. Another one is go to definition stuff, I want to see the real declaration of any class or method or even a variable.

Also I know that it can handle the make files but an actual representation of a project alongside the editor would be very good. So, what I am asking is, is there a way to provide these options in Emacs? Or is there an extended version of Emacs that supports these features?