1. Coding Question-https://leetcode.com/problems/merge-k-sorted-lists/description/
2. Java 8 new features
3. Stream API - Difference between toList() and collect(Collectors.toList())
4. Fail Fast and Fail Safe Iterator
5. usual code based question on iterator- what happens if we try to use list.add and list.remove in for each loop. how to avoid it.
6. Colletios.sort() - which sorting algoriothm is used here
7. Concurrent HashMap - how it works
8. Executor Framweork - which threadpool have you used- how many threads will you create for 1000 tasks in fixed threadpool.
9. Completable Future
10. Spring security - how to invalidate JWT token
11. Builder Pattern
12. Observer Pattern - comparison to kafka
13. In memory Cache

Rejected.