The interview was medium level. Though I did a lot of preparing on Java, multithreading, and coding, I was not fully prepared for DB (Hibernate) and resilience-related questions. It was a nervous interview.

What is Lock, ReentrantLock, synchronized? How to make threads run in sequence? Wildcards, e.g., of wildcards. Bus ticketing design system. What is the difference between TreeMap, HashMap, ConcurrentHashMap? How to handle a service which has used up full memory? Lifecycle of a bean. Transactional annotation and its attributes. What is a microservice? How do 2 or more services behave in case of failure of any one of the services? How to handle it? Long to short URL design.