Mastercard Software Engineer II interview questions

There are 3 rounds of interviews. all of them are technical and based on the technology you're shortlisted for. They were supposed to be scheduling next round but I never heard from them. Pathetic experience from HR.

I applied via Mastercard Website and on a random day I got the email saying that I was selected for pre screening round and should wait for an email or phone number from the interviewer. I was happy and started preparing for it right away. This was on Monday. I waited the whole and and the next day but yet no call on an email. Cut to Wednesday morning which was a holiday here I receive and email saying that it has been fun talking to you and we are moving ahead with another candidates. Now this actually pissed me off since I was wondering whom did they talk to, So I dropped the email to privacy and protection regarding fraud which then got assigned and then I received a call next week from the Mumbai office TA apologizing for this behavior. Her reason : They already got a candidate for the same position. Now I don't know how they got a candidate within 2 day - was it a via referral or string connection, or they were already winding up the candidates they had, or organizational restructure but whatever reasons they have this does not give them any right to toy with people feelings. So what if they had a candidate in hand they could have moved ahead with him/her and not bother me with the email AT ALL. Life would be going as it is. But I was a little bit glad that she acknowledged this and then scheduled an interview by asking relevant questions. She scheduled it on Thursday but I told her to schedule it on Monday as Friday was a holiday. She told be there will be no assurance that by that time they will get a desired candidate for it - I mean like how are they hiring ???? Still, the interview failed to show up on Monday, I dropped an email after 10 min wait and then she scheduled for the next day. The interview was alright - asked me Java questions