Spotify Android Engineer - Experience Mission interview questions

The process took 4 weeks, but I only did two interviews before getting rejected. Because it was summer, most of the people was taking vacations, including the recruiter, so I had to wait a long time between the interviews. The first step was a phone interview with the recruiter that happened 6 days after I applied. It was a 30 minutes call about my background and my skills and general information about Spotify. The next day, I received an email saying that they wanted to schedule the next meeting and asking for dates. I answered, but only heard back from them 10 days later, because the recruiter went on vacation without telling me. So I finally had the next interview (18 days after the first interview). This was an one and half hour online tech interview divided in three parts: - 30 minutes questions about Android and Computer Science general concepts. - 30 minutes coding challenge (implement a countdown timer). - 30 minutes code review challenge (review a pull request that had a lot of problems - had to have knowledge about threads and broadcasts to fully understand the code). They were all very nice, but I hadn't prepared myself very well, so I already knew I wasn't going to get an offer. 4 days later, they got back at me saying they would move forward with other candidates.