Java Backend Developer Interview Questions & Video Screens

Introduction

Hiring the right Java Backend Developer is critical for IT teams building scalable, reliable services. A strong backend engineer improves performance, security, and developer velocity while ensuring systems integrate cleanly across the stack.

This guide provides screening-ready Java Backend Developer interview questions across basic, intermediate, and advanced levels, plus five pre-screening one-way video interview questions ideal for early-stage filtering on platforms like ScreeningHive.

Java Backend Developer Interview Questions

Basic Java Backend Developer Interview Questions

• Explain the difference between JDK, JRE, and JVM.
• What are the key features of Java 8? Mention at least two and explain why they matter.
• Describe the Java memory model and the roles of heap and stack.
• How does garbage collection work in Java and what are common GC algorithms?
• What is the difference between checked and unchecked exceptions?
• Explain the concept of immutability and give an example of an immutable class in Java.
• How do you implement a thread-safe singleton in Java?
• What are streams in Java and when would you use them over loops?

Intermediate Java Backend Developer Interview Questions

• Describe how you would design a RESTful API in Java. Which frameworks would you consider and why?
• How do you handle transactions in a Java application interacting with a relational database?
• Explain connection pooling and why it is important for backend services.
• Given a performance problem in a Java service, how would you profile and identify the bottleneck?
• How do you implement pagination and filtering for large datasets in a backend endpoint?
• Describe strategies to ensure backward compatibility for evolving APIs.
• How do you secure sensitive data in transit and at rest within a Java backend?
• Explain how you would implement caching in a distributed Java application and trade-offs to consider.
• How do you handle retries and idempotency for external service calls from a backend?
• Discuss how you would design asynchronous processing in Java (e.g., message queues, CompletableFuture).

Advanced Java Backend Developer Interview Questions

• Design a microservices architecture for a high-throughput system. How do you manage service discovery, versioning, and failure isolation?
• Explain JVM tuning for low-latency services. Which GC settings and memory configurations would you adjust and why?
• How would you implement distributed tracing and correlate requests across multiple Java services?
• Describe patterns for data consistency across services (e.g., saga, event sourcing) and when to use each.
• Discuss trade-offs between synchronous and asynchronous communication in microservices and how to choose between them.
• How would you approach designing a schema and migration strategy for high-availability databases used by Java backends?
• Explain how to handle backpressure in a reactive Java application.
• Describe techniques to optimize cold-start and warm-up behavior for Java services in containerized environments.
• How do you evaluate and improve throughput and latency at scale, including benchmarking and load testing approaches?
• As a senior engineer, how do you mentor team members and lead technical design reviews to improve backend quality?

Pre-Screening Video Interview Questions for Java Backend Developer

These five one-way video interview questions are ideal for ScreeningHive pre-screening. They assess technical knowledge, problem-solving, architecture thinking, and communication—helping hiring teams quickly shortlist qualified Java Backend Developer candidates.

1. Describe a recent backend project you worked on and your primary responsibilities.

   This evaluates practical experience, role fit, and communication—look for clarity on scope, ownership, and specific contributions.

2. Explain how you diagnose and fix a memory leak in a production Java service.

   This assesses troubleshooting skills and familiarity with JVM tools, heap dumps, and root-cause analysis.

3. Walk through how you would design a REST API for a resource-heavy endpoint that must support high concurrency.

   This checks design thinking, scalability considerations (caching, pagination, rate limiting), and framework choices.

4. Describe how you ensure secure handling of user data in backend services (authentication, authorization, secrets management).

   This measures security awareness and practical controls such as token-based auth, encryption, and secret vault use.

5. Give an example of a time you improved performance in a Java backend. What did you measure and what changed?

   This evaluates impact, use of metrics/observability, and ability to deliver measurable improvements.

Conclusion

This collection of Java Backend Developer interview questions helps hiring managers and recruiters standardise technical screening across junior to senior levels. Candidates can also use it to prepare for technical and architectural discussions.

ScreeningHive supports one-way video interviews for efficient, standardised evaluations, enabling faster screening and consistent candidate assessment. Start a FREE sign-up to streamline your Java Backend Developer hiring process and reduce time-to-hire.