I applied for a (different) Amazon job in the Summer 2014. I didn't get it, but it kept my resume in their database, and I was a contacted by a recruiter a few months later for this position. We corresponded a few times via email, and she sent me the online link for the first step of their interview process. The first part was a general intelligence / analytical / brain teaser test where they pay attention to how well you understand and process paragraphs, mental math, and other quick response questions. This part was fine. They then moved on to the actual coding test part. This was a little strange as they turn on the webcam on your computer to ensure the legitimacy of your test. You could pick your language (C++ or Java) and answer the questions accordingly. I struggled with both. In retrospect the questions were very easy and I struggled only because it was very early on in my hiring process and I hadn't found my 'coding rhythm' yet. Work through a coding interview prep book for a few weeks and you should be fine.