Amazon Software Development Engineer II interview questions

For the onsite interview at Seattle, Amazon paid me everything including flight, accommodation, local transportation and food. I was interviewed by 6 people, 1 of which came from human resource group. Coding questions were not challenging, but many system and OO design questions were asked. I was not quite familiar with the design-type questions, which should have been prepared well in advance. Overall it was a great interview experience. Although I did not get an offer, I learnt a lot on my weakness.