Questions posées lors d’un entretien d’embauche pour Senior Java Microservices Developer chez Oracle

1. Project Discussion: I was asked to explain the current architecture of my project. I spoke about our microservices-based payment platform using Spring Boot, Kafka, Redis, and PostgreSQL. 2. Deep Dive into Challenges: They asked about the most challenging issue I faced. I shared how we handled message duplication and retries when Kafka consumers failed and how we used Redis for idempotency. 3. Core Spring Concepts: Questions included: Scopes of Spring beans, Use of Prototype scope and related implementation, Common mistakes with Singleton beans, How to exclude packages from component scanning 4. Transaction Management: They asked about @Transactional and how Spring manages transactions under the hood. 5. JPA & Hibernate: Topics included: Features of JPA, Optimizing queries to prevent repetitive DB hits 6. Kafka Scenario-Based: A practical scenario: what to do when a Kafka producer fails. I explained storing failed messages, retry strategies, DB optimizations, and caching using Redis.