Java Microservices Developer Jobs in Oshawa, ON (NOW HIRING)

We are seeking a skilled Backend Developer to join our team on a 1‑year fixed-term contract. In this role, you will design, build, and optimize high‑performance backend services using Core Java and Spring Boot, with a strong emphasis on multithreading, concurrency, and scalable microservices.

You will contribute to the development of AI‑enabled and agentic systems, support distributed architectures, and partner with cross‑functional teams to deliver resilient, low‑latency solutions. This is an ideal opportunity for someone who enjoys solving complex backend problems, working close to the JVM, and applying modern engineering and AI-driven patterns at scale.

• Design, develop, and maintain backend services and APIs using Core Java (8/11/17+), Spring, and Spring Boot, applying advanced multithreading and concurrency patterns to build high‑throughput, low‑latency systems.
• Contribute to agentic AI–enabled backend workflows, supporting Java-based AI orchestration, service coordination, and intelligent processing within distributed environments.
• Work within a microservices architecture, integrating RESTful services, messaging platforms (Kafka/RabbitMQ), and relational databases while ensuring scalability and clean separation of concerns.
• Diagnose and resolve performance bottlenecks through profiling, JVM tuning, thread pool optimization, and garbage collection analysis, improving system reliability and throughput.
• Collaborate with frontend and full‑stack teams by supporting backend integrations with HTML, Angular, and TypeScript applications, ensuring efficient API design and data contracts.
• Implement unit, integration, and performance testing, contribute to CI/CD pipelines, and support deployment within containerized environments.
• Enhance service observability and resilience through logging, metrics, tracing, and fault‑tolerant patterns, while contributing to secure coding practices and technical documentation

This is your opportunity to work in Operate at Deloitte. Operate services harness the latest technologies, talent, and capabilities from all over the world to deliver ongoing outcomes and client value. We do more than traditional business process outsourcing. We do more than just “keeping the lights on.” We work shoulder-to-shoulder with clients and their customers, constantly adapting to the pace of change, to ideate, innovate, and embed continuous advantage at the heart of their operations. And we do it with the kind of drive and passion that comes from loving what you do—and who you do it with.

You are someone with these skills, experience & qualifications:

• 6+ years of professional Backend Development experience using Core Java (8/11/17+) 
• Strong hands‑on expertise in Concurrency & Multithreading, including:
  • Thread safety, synchronization, locks, atomics
  • Executors, thread pools, fork/join, CompletableFuture
  • Non‑blocking and asynchronous processing patterns
• Solid understanding of JVM fundamentals, including memory model, garbage collection, heap/stack behavior, and performance tuning
• Extensive experience with Java, Spring, Spring Boot, and microservices architecture
• Experience building Agentic AI–enabled backend components using Java (e.g., AI orchestration, intelligent agents, workflow coordination)
• Strong experience developing RESTful APIs and integrating with distributed systems
• Proficiency with SQL and relational databases (PostgreSQL, Oracle, MySQL), including query optimization; exposure to NoSQL (Redis, MongoDB) is an asset
• Exposure to frontend technologies (HTML, Angular, TypeScript) to support backend‑to‑UI integration
• Strong testing skills using JUnit, Mockito, Testcontainers; experience with performance testing tools is a plus
• Experience with CI/CD pipelines, version control, and containerization (Docker, with Kubernetes exposure preferred)
• Familiarity with observability tools for logs, metrics, and tracing
• Solid grasp of SOLID principles, clean code, and backend design patterns
• Strong communication skills and the ability to work effectively within Agile delivery teams

The salary range for this position is $72,000 - $138,000, and individuals may be eligible to participate in our bonus program. Deloitte is fair and competitive when it comes to the salaries of our people. We regularly benchmark across a variety of positions, industries, sectors, targets, and levels. Our approach is grounded on recognizing people's unique strengths and contributions and rewarding the value that they deliver.
Our Total Rewards Package extends well beyond traditional compensation and benefit programs and is designed to recognize employee contributions, encourage personal wellness, and support firm growth.  Along with a competitive base salary and variable pay opportunities, we offer a wide array of initiatives that differentiate us as a people-first organization. On top of our regular paid vacation days, some examples include: $4,000 per year for mental health support benefits, a $1,300 flexible benefit spending account, firm-wide closures known as "Deloitte Days", dedicated days of for learning (known as Development and Innovation Days), flexible work arrangements and a hybrid work structure.