Amazon Software Developer interview questions

Applied online through as a new Graduate. They called and asked to set up an interview. First interview was lots of questions based on material like what are the 5 Principals of Object Oriented Programming. They ask lots of questions about your former work (if you only have school projects they ask you to talk about what you did). They will then ask you questions about those projects such as what programming designs you used (Singleton for example) and ask what characteristics that design has. The last 15 minutes of the interview is a programming question. My question was to write a method that sorts 2 Array's into one. You write this code quickly and tell them over the phone how you wrote it (including parentheses commas, ect). He asks you clarifying questions like if you wanted this to run faster how might you right it, and assuming we wanted duplicates how would you need to modify the code. The second interview was much more programming based. 20 minutes was general questions followed by a programming question which was done online on a website where both the interviewer and the interviewee could both see and work on the code. I forget what this code was but its a fairly simple method to write. At the end of the interview I was asked to write a method for StringToDouble in the next hour (following the end of the interview) and then to email it to the interviewer. This method had to include thorough error checking and a method to test various cases (invalid characters, double too large, ect).