Amazon Software Development Engineer interview questions

It was really unexpected that so many questions were based on object oriented conceots

I was contacted by a recruiter and flown to Seattle. After a couple of hours of talking to engineers and asking questions, I spent the rest of the day doing a group programming problem. I can't go into detail about the question, but it was such that every member of the group could work on a seperate part. I thought I did pretty well, but I guess they were looking for something else, or maybe I didn't give the right impression during the 30 minute 1 on 1 interview in which we discussed the code I had written so far and talked about what I wanted to do at Amazon.