I didn't had a good experience with Mantra Labs. This company is very small and is just on 1 floor with a big hall and 2-3 meeting rooms. The place doesn't have a good vibe. The most funny thing is that the company CEO itself takes the final round and he is very rude and arrogant. I actually knew this before the interview as I read it on glassdoor and had the same experience. There were 4 rounds in total at Mantra Labs. I was called for Java & Cassandra interview. But during the interview they asked me Java and MySQL. They told that they don't have any interviewer for Cassandra. The entire process took about 5-6 hours and it was a waste of time for me. Round 1 - It was a basic Java round with few programming question and SQL. Round 2 - It was more of SQL round and few Java question again. Round 3 - It was more of Data Structures and Algorithms round where the interviewer asked me programs on Linked List and all. Round 4 - It was the final managerial round where that CEO fellow came in. He asked question on Maths , Java and also Salary discussion, In the end he said I am expecting much more salary than they can offer. He said that if somebody gives you this amount then you should definitely join that company. At the end he wanted that the people in his company should work always even on saturday and sunday. I dont know how he started a company.