Round 1 : F2F: Difference between polymorphism, abstraction, inheritance. Inversion of control. When do we use lambda exps. in java? Detect a loop in linked list. Given a sum, find 2 integer in the array adding upto that sum. in O(n) Puzzle - Different denominations of money in 10 bags, Weigh only once problem. Round 2 : F2F Design backend API structure for a comment section. Example like facebook comment Recursive program for factorial and sum of n numbers.