Grammar about series

Try to Make some Projects and then you will came to know about java, c , c++ or .net

i really want to ask the structure of this sentence.
"i have x, y, or z ."
Does it means
a)I have x or I have y or i have z
b) I have x and y , or i have z

You wouldn't say something like if you were describing your programming experience. Either you have experience in all of these programs, or you don't. You would write: "I have experience with Java, C++, C# and Ruby." If you use "or," it doesn't make any sense, and it is not going to impress a prospective employer. They want to know what your experience is, they don't want to play incomprehensible word games.

i was trying to apply internship but the requirement confused me
http://blogs.adobe.com/adobelife/jobs/posting/245642/machine-learning-and-data-science-intern/

That's really a god q, Ckj, one I've long pondered. It's like, is the comma necessary in "He spoke with Bill, Ed, John and Max." I maintain it needs another comma, after John, to avoid the implication that John and Max bear a special relationship not shared with Bill and Ed