Java Technical Interview Questions | Epam Systems

Java Core

• OOP
• HashMap internals like how put() method works - good explanation
• Arraylist vs LinkedList how they differ
• abstract class vs interfaces
• access modifiers, default vs protected
• How to create Thread in java
• what is DeadLock, LifeLock?
• Do you know something about ThreadPool
• StringBuilder vs StringBuffer, what is the difference
• What is GC, how does it work, can you name some popular GC, can we call it?

Spring Core

• Advantages of Spring
• Bean Scopes
• What is IoC, DI
• DI types (e.g constructor ...)
• Design Patterns used in Spring
• what is transaction, how to enable it in Spring (hint @Transactional)
• ACID
• can you describe request life cycle in Spring MVC, how it looks like (hint: DispatcherServlet)

Hibernate

• what is ORM, implementations
• entity relationships

REST

• what is REST?
• can you name Richardson Maturity Models?
• @RestController vs @Controller

No SQL

• SQL vs NoSQL
• can you list some NoSQL databases

Spring Boot

• difference between Spring vs Spring Boot
• profiles
• actuators
• how to disable auto configuration in Spring Boot

Spring Security

• do you know about OAuth2, what is it? 

TDD/BDD

• what is TDD, BDD
• what is scenario, can you give example

Messaging

• sync vs async

Microservices

• Monolith vs Microservices
• Pros and Cons of Microservices
• Desing Patterns in Microservices

AWS

• EC2 vs Lambda
• Advantages of Serverless
• synchronous call vs asynchronous call