Persistent Systems Interview Question

Martian program by persistent systems technical interview: the interviewer started with basic questions like introduce yourself, which is your fav subject. OOPS- 1. super class 2. polymorphism 3.interface DS- 1. diffrence between array and linked list DBMS- 1. joins 2.union and union all Lastly, why persistent? why should I hire you? how was your interview? how am I taking interviews? just one advice- be confident and if you don't know the answer pass it rather than bluffing around.