Round 2 questions were mainly based on fundamental concepts. Difference between interface and abstract classes, polymorphism- difference between overloading vs overriding, merge sort algorithm and explanation of why it runs in O(n logn), tree traversal (BFS,DFS), stack queue. There were also 2-3 algorithmic questions on design of basic algorithms and DS like checking if a singly link list has a loop and counting frequency of digits from a 16GB file of only numbers if you can only fetch 1GB into the RAM at a time (using appropriate data structures to address space complexity). Also, a few questions on hash maps because I kept using them too frequently in answers.
