BlackRock Software Engineer interview questions

I have one-round in-campus interview first. And then I got an email to be onsite. There are four rounds interview onsite. In the first round, it seems that he is interested in my project. He asked me to design a recommending system for room booking. We discussed about the features of a room and how to use this feature to recommend room for the user. The second round is about the technical quetions. He asked me about the multi-thread and lock questions in Java. Actually I am not familiar with Java multi-thread so I am feeling not good in this round. In the third round, he asked me if I am good at multithread and I said no. He keeps asking knowledge questions instead of algorithm questions. In the fourth round, he asked me so SQL queries but they are quite easy.

The interview process was easy. First a phone interview and then super day. Super day is in seattle and I flew to seattle for 5 interviews. Two of the rounds were technical and the rest are partially technical