[Trifoilum]

....uuuum, to people who live, or lived, or been in Japan, I need to ask pertaining your experience of living there for a while..

As part of my final paper in my local college I'm planning to do some research of Food takeouts in Japan, like the "pick a meat dish and two vegetables" kind of joint, not izakaya. Here I have these kind of foodcourts but they are mostly Chinese or local food so I can't find out more :| Based from..several manga I read, they also seem to exist in Japan?

My question is:
1) What do they called? In kanji or in furigana, so I can try and do some research by myself too
2) Do a lot of them exist? What type of place are they? What class do these places usually are?
3) What are the dishes they sold? Are they similar between joints, or say, areas?
4) How do they work?

any help I could get would help so much Thanks in advance!