Persistent Systems Interview Question

Technical they asked this 1. Inheritance 2. Modifiers 3. Functions 4.SQL queries 5.internship 6.project of whatever I did for internship as well as final year project and they asked how I can make it better. 7. Software engineering questions like waterfall model (they actually asked what I should do if a client wants a software and the procedure I should follow so I gave waterfall model example) 8. OS they asked about deadlock 9. Also Windows and Linux