Birdeye Java Developer interview questions

There were total 4 rounds. 1st round : HacktRank Test, there were 3 questions and 1 Sql Query. All the Question were between Easy To Medium 2nd Round : F2F, So I thaught it went Good because i probably gave most of the answer, i was not able to give 1 DS solution and 2-3 theory questions. Interview went on for almost an hour they asked me lots of questions. In the end i thaught i cleared but HR told me leave for the day. I really did not understand why interviewers do this. Next two rounds include 1 more F2F and then HR.