Amazon Sr Software Engineer interview questions

A recruiter from Amazon got my resume from Dice and called me. I did not have the exact skill sets for the job description for which I was to be interviewed but the recruiter informed that at Amazon they are looking for people with sound software engineering background and the exact skill set or experience in a particular programming language did not matter. The recruiter setup a phone interview for an hour. I could not attend the interview as my daughter was sick. So, the interview was rescheduled with no problems. The interviewer was very calm, giving me plenty of time to think and come up with an answer. He also gave me tips to lead me in the right direction. Overall the interview experience was very good. It was an hour long interview. Questions asked: 1. How would you implement a hash map in java if for some reason you cannot use java.util.HashMap class? 2. Can any class be used with an enhanced for loop i.e. for each loop in java? 3. How would you implement threads in java. Go over all the details of join, wait etc. 4. Why do you want to work at Amazon?