Dice Enterprises Pvt Ltd. Java Back end Developer interview questions

There were 3 rounds of Interview out of which 2 were Technical one and 1 was HR. There were questions form DP on Strings like LPS and SCS and discussion went well on my work experience. There were questions from Design and optimization of system like "If you have an API which provide data but each client want some specific sort of data and not the full set fo attributes So how would you optimise API for that scenario" Then I was asked to write API's in spring boot (REST) and test it down with postman. There were questions from OOPS JAVA. First round is off around 2 hours My Interview went well and got shortlisted for 2nd round. In 2nd I was asked to code DSA question without Collection Framework. Despite both rounds went well and positive feedback from Interviewers, I was not given the offer. The worst experience and communication I ever had.