Senior developer Java

Description

Auto-generated position for Senior developer Java

Interview Questions (113)

Q1Can you describe a challenging bug you encountered in a Spring Boot application and how you resolved it?
Technical
Q2Tell me about a time when you had to work in a team to meet a deadline. What was your role?
Behavioral
Q3Can you describe your experience with building microservices using Spring Boot and how you managed service communication?
Experience
Q4How would you handle a situation where a critical microservice goes down in production?
Situational
Q5List three Collections interfaces and the basic contract of each. List concrete implementations of each, how they differ, and performance characteristics in space and time.
Technical
Q6Describe the contract of equals and hashCode. Why is it important that if you implement one, that you implement both?
Technical
Q7What is a deadlock? How can you prevent it?
Technical
Q8What is a race condition and how do you avoid it?
Technical
Q9What are the different statement types and why would you use each?
Technical
Q10How do you prevent SQL injection attacks?
Technical
Q11What are transactions?
Technical
Q12Give an overview of Hibernate and ORM. How do you load objects into the session? What does the session do with the objects while in the session? What is the difference between getting a persistent object from the session and querying for persistent objects?
Technical
Q13When is it better to use plain SQL instead of ORM?
Technical
Q14What are some ways for the client to obtain a reference to the DataSource from the app server?
Technical
Q15What is the difference between SOAP-based web services and REST-based web services?
Technical
Q16Describe SOAP and WSDL.
Technical
Q17What exactly is REST? What is the purpose of each of the HTTP verbs? What is idempotence? What is content-negotiation?
Technical
Q18What is decoupling? Why are loosely-coupled classes desirable? What are some drawbacks?
Technical
Q19What is cohesion? Why are highly cohesive classes desirable? What are some drawbacks?
Technical
Q20Describe polymorphism. What is the importance of contracts between interfaces and concrete types? Why is polymorphic code desirable? What are some drawbacks?
Technical
Q21What’s the purpose of `volatile`?
Technical
Q22How does `ThreadLocal` work?
Technical
Q23When should you use `Callable` over `Runnable`?
Technical
Q24How is `HashMap` implemented internally?
Technical
Q25What is the difference between `ArrayList` and `LinkedList`?
Technical
Q26When to use `ConcurrentHashMap` vs `Collections.synchronizedMap()`?
Technical
Q27What is fail-fast vs fail-safe iterator?
Technical
Q28How do `TreeMap` and `HashMap` differ?
Technical
Q29What are the four pillars of OOP in Java?
Technical
Q30What is the difference between composition and inheritance?
Technical
Q31What is the Liskov Substitution Principle?
Technical
Q32Can an interface have static methods?
Technical
Q33What is garbage collection in Java?
Technical
Q34Explain the Java memory model.
Technical
Q35What is PermGen vs Metaspace?
Technical
Q36How does G1GC differ from CMS?
Technical
Q37How can you detect and fix memory leaks?
Technical
Q38What is a functional interface?
Technical
Q39Difference between `map()` and `flatMap()` in Streams?
Technical
Q40What are method references?
Technical
Q41What is Optional and how should it be used?
Technical
Q42What is the purpose of default methods in interfaces?
Technical
Q43How does Spring Boot auto-configuration work?
Technical
Q44Difference between `@Component`, `@Service`, `@Repository`?
Technical
Q45How does Spring manage bean lifecycle?
Technical
Q46What is the role of `@ConditionalOnProperty`?
Technical
Q47How do you implement inter-service communication?
Technical
Q48What is the difference between synchronous and asynchronous calls?
Technical
Q49How do you implement retry, fallback, and circuit breaker?
Technical
Q50How do you ensure backward compatibility between services?
Technical
Q51What’s the role of API Gateway in microservice architecture?
Technical
Q52How do you secure REST endpoints?
Technical
Q53What is the difference between OAuth and JWT?
Technical
Q54How do you implement RBAC in Spring Security?
Technical
Q55How do you protect microservices against DDOS or abuse?
Technical
Q56What is rate limiting and how do you implement it?
Technical
Q57What is Spring Cloud Config Server?
Technical
Q58How do you implement distributed tracing?
Technical
Q59How does actuator help in production?
Technical
Q60How to monitor microservices in real time?
Technical
Q61How do you achieve zero-downtime deployment?
Technical
Q62What is blue-green deployment?
Technical
Q63What happens if a service crashes? How do you recover?
Technical
Q64How do you handle data consistency in distributed transactions?
Technical
Q65What is a Saga pattern and when should you use it?
Technical
Q66What is the Singleton pattern? How do you implement it in Java?
Technical
Q67How is Factory pattern different from Abstract Factory?
Technical
Q68What is the Strategy pattern?
Technical
Q69Where is the Builder pattern commonly used?
Technical
Q70What is the Observer pattern?
Technical
Q71Explain the Proxy pattern with real-world usage.
Technical
Q72Difference between Adapter and Decorator pattern?
Technical
Q73What is the Template Method pattern?
Technical
Q74When do you use Command pattern?
Technical
Q75What’s the benefit of Chain of Responsibility?
Technical
Q76What is Dependency Injection? How does Spring use it?
Technical
Q77How is MVC implemented in Spring?
Technical
Q78What is AOP? Common use cases?
Technical
Q79How is Lazy Initialization useful in patterns?
Technical
Q80What’s the difference between Composition and Aggregation?
Technical
Q81Can patterns introduce complexity? How do you balance it?
Technical
Q82What’s the role of the Mediator pattern?
Technical
Q83Example of Flyweight pattern in Java APIs?
Technical
Q84How do you reverse a LinkedList without using extra space?
Technical
Q85Write a function to check if a string is a palindrome.
Technical
Q86What is the time complexity of HashMap operations?
Technical
Q87Explain binary search algorithm.
Technical
Q88How does QuickSort work?
Technical
Q89What’s the difference between BFS and DFS?
Technical
Q90When is a heap used in Java?
Technical
Q91Implement LRU cache.
Technical
Q92What’s a Trie? Use case?
Technical
Q93What is the difference between a stack and a queue?
Technical
Q94How do you detect a cycle in a graph?
Technical
Q95How do you find the intersection of two arrays?
Technical
Q96What’s the difference between Array and LinkedList?
Technical
Q97What is dynamic programming?
Technical
Q98What is memoization?
Technical
Q99Difference between INNER JOIN and LEFT JOIN?
Technical
Q100What is normalization?
Technical
Q101How to prevent SQL Injection in Java?
Technical
Q102What is indexing? How does it work?
Technical
Q103Difference between clustered and non-clustered index?
Technical
Q104What is ACID in databases?
Technical
Q105Explain isolation levels.
Technical
Q106What are transactions and how are they managed in Spring?
Technical
Q107What’s a deadlock in DB?
Technical
Q108How to profile slow queries?
Technical
Q109What’s the use of `JOIN FETCH` in JPQL?
Technical
Q110How do you ensure consistency in distributed DBs?
Technical
Q111What is the difference between optimistic and pessimistic locking?
Technical
Q112When to use NoSQL over RDBMS?
Technical
Q113What’s a primary key vs unique key?
Technical