Round #1 - Initial screening via video conference with a Senior SE

1. Tell me about yourself?
2. What are the design patterns you've worked with?
3. Why OOPS?
4. What's reactor design pattern?
5. What was the challenging work you've done so far?
6. What were the code standards did you team follow and how did you all define them?
7. What's the lookup time for a Hashset?
8. What do you know about multi-threading?
9. What is an abstract class and interface?
10. Leetcode question   -
    https://leetcode.com/problems/day-of-the-week/
    (cannot use date time libraries