Job Title: Senior Backend Java Developer

Location: Mississauga, ON

6 months contract to hire

3 days onsite per week

Required Skills & Experience

- 8+ years of experience in application development or systems analysis, with a heavy emphasis on Java-based backend architectures.
- Deep, expert-level understanding of Core Java (Java 11/17/21), including advanced multithreading, concurrency models, Java memory model (JVM garbage collection, heap analysis), and Collections API.
- Extensive hands-on experience building distributed data processing systems, ETL pipelines, and real-time streaming architectures using tools like Apache Kafka, Apache Spark, Flink, or Hadoop.
- Strong experience with the Spring Ecosystem (Spring Boot, Spring Cloud, Spring Data, Spring Security) and ORM frameworks (Hibernate/JPA).




- Proficiency in designing schemas and writing optimized queries for both relational databases (e.g., PostgreSQL, MySQL, Oracle) and NoSQL stores (e.g., Cassandra, MongoDB, Redis).
- Comprehensive understanding of distributed system design patterns, consensus protocols, caching strategies, and API design (RESTful APIs, gRPC).
- Practical experience with containerization (Docker, Kubernetes), continuous integration/continuous deployment tools (Jenkins, GitLab CI, or GitHub Actions), and infrastructure-as-code principles.
- Solid advocate for testing frameworks such as JUnit, Mockito, and integration testing tools.

📌 Senior Backend Java Developer - toronto
🏢 Kelly
📍 Toronto