Least professional interview process so far.
First, they called me on the wrong day, which led to a very uncomfortable interview experience. They did however acknowledge the mistake and had me reinterviewed. For the next interview, after asking for my availability, they scheduled an interview at a time that I clearly said doesn't work for me. After two phone interviews following the mistaken one, I was told me that the last step would be a coding challenge as I am applying for an internship. However, after doing well on that, they asked for another on-site interview. I reminded the recruiter that I’d been told the last step would be the coding challenge and informed them that I would need to decide in 2 weeks (giving exact date), so an on-site would be impossible. She corrected herself and said that all that's left is reference check.
Immediately after I sent the references, she came back again and asked for another interview. We scheduled that for the next day. I assume they wanted to test something spark related on their platform, but the interviewer couldn't get their website to send me a confirmation link for my account in time, and his direct invites didn't work either, so we did some more basic coding questions. Not sure why this was necessary as he literally asked me to write the simplest recursion possible. He even asked me multiple times if I had seen the question before, which was absurd as no one remembers something as trivial as if they have written a for loop with an increment of 9. It felt more like a test of honesty than anything else. On top of all this, the interviewer for my coding challenge was 35 minutes late because of Bart, and seeing how all he had to do was send me the email with the challenge, I don’t see why someone else couldn’t it instead.
At this point, they had 5 full business days after all the interviews were done and more than that with my references, before the deadline that I gave them. I emailed them once during the last week to ask if they need something to speed up the process and ensure nothing is blocking them. They didn't tell me anything before the deadline.
3 business days later, I emailed them to make them tell me that day what they are deciding. It was only then that they emailed me and finally rejected me. One of my references said they cancelled the call with him the week before, so if they had decided then, I don't see why they wouldn't tell me.
The interview questions are pretty standard. The coding challenge took 6+ hours the first day before I sent it for review, and then about 4 hours the second day. I can't judge its difficulty correctly, but given that I spent most of the time figuring out how to write proper tests and doing synchronization in Java and got a positive feedback, I don't think it should be a problem for anyone more familiar with those things. The whole process took 6+ weeks.
Would NOT recommend interviewing here.