There are 3 stages in the interview process:
1) Phone call. This stage contains some general questions about java, sql and simple math task. This is not difficult stage. I guess it's needed only to filter candidates.
2) Technical Interview. This is a prettty hard step. You should expect advanced questions about concurrency (JMM especially race conditions, hb and liveness problem), java object (how it represented in jvm), collections, GC (different types, tuning, roots) and tasks to test knowledge math and sql.
3) Interview with managers. There are a lot of logical brain teasers and some algorithms questions.
All question should be answered pretty quick and answers do not count if you use many tips.
All interviewers were pleasant persons and made a good impression.
Unfortunately I had a lack of experience for this position so I did not get an offer, but I had positive and detailed feedback.