Morgan Stanley Software Engineer interview questions

I applied through college.There was an online test which included 30 mcqs and 3 easy level programs to be coded.I was shortlisted and next round was a group activity at their office.It was about building a functional component for their company and market it.I wasnt selected for this round

How to reverse an string without using extra memory? When, why and how we use Polymorphism? Why we use inheritance? Why object oriented? Java framework specification and benefits. Combine two string. Basic SQL questions. Implementations of sorting and searching algorithms like merge sort. Best data structure fore different purpose. Best sort and search algorithm.