First round: Zoom call. I was approached by a consultancy HR who found my resume on Naukri. The interview went on for 45 minutes. The interviewer was neutral. He asked questions related to the areas that I had previously worked on.

Questions asked to me are listed below.

Database:

• Read large CSV file (4 columns) and store it in DB.
• Why Oracle over other DBs?
• Why foreign key?
• Difference between PK and FK.
• Unique vs. Primary Key.
• Joins.

Core Java:

• Describe JVM.
• Cron job: How to schedule.
• Execute multiple transactions to different APIs in parallel.
• Schedule: Cron job.
• Scope in POM dependency.
• ClassNotFoundException vs. NoClassDefFoundError: How do you resolve them?
• Mockito.
• Where do we deploy our application?
• MQ.
• Logging.
• Levels of logging.
• Factory vs. Singleton design patterns.
• What does IntelliJ debugger use internally? Ans: Java reflection.
• Exception Handling.
• How to create our own exceptions.
• Can NPE be extended?
• What is the other class that can be extended?
• Try-catch-finally.
• Hierarchy of catch.
• Difference between exception and error.

Spring:

• Tight coupling.
• Loose coupling with examples.
• Dependency injection and IoC.
• Singleton and prototype use case questions.
• Bean scopes.
• Autowiring types.

Hibernate:

• Caching.
• If there is no CacheManager, how do we write our own caching mechanism?
• Change the connection configurations (application.properties).

WS:

• Difference between SOAP and REST.
• Is XML better or JSON better? Why?
• Filters.
• Validations.
• Difference between Controller and @RestController.
• What does 'State' stand for in Representational State Transfer?