Tech Mahindra interview questions

It was a walk in drive , first round was technical which was kind of easy with only basic of core SAP and little bit of OOPS concept , I cleared it and was told that second round would be an aptitude test by next three four days as I have less than 40 months in experience , but instead suddenly I got a call from them that they have arranged a client interview and I have to clear it as well , later I cleared both client interview and aptitude exam , I was told that I will get a call from hr for further process but its been weeks and I am still waiting. Can't understand if they don't have opening why waste time of candidates , and why so many rounds instead of saying no. It's frustrating.

Interview was fully technical based. They asked me about oops concepts and as well as some dbms questions. Then they asked me about the projects i have done and i was talking primarily on the skills that i have learnt from the project development.