3 rounds on 1-O-1 interview

On day one, there was a telephonic for about 35 min. It was mainly Java and the current project. Java part was on Immutable object, deadlock, threads and questions on http concepts, serialization. I have got an email the same day asking to come for F2F interviews. It consisted on six rounds, each of them by a separate single person, from 10 am to 5 pm. It was totally data structures, architecture/deployment based like - design (did not ask any design patterns in specific though) of db schema, layers, etc. However no puzzles were asked. Some questions from data structures - traversing a linked list, binary tree (BFS), stack operations.