# of Openings: 1Client: Investments IndustryType: 6-Month Contract (targeted through September; extension possible but not guaranteed)Location: Downtown Toronto, ON (Mon-Thurs Onsite (4 days/week)) 37.5 hours/weekCollabera is seeking a Senior Java Software Engineer to support a large-scale modernization initiative focused on transforming legacy and third-party systems into scalable, cloud-based architectures.This is a high-impact, problem-driven role—not a ticket-based environment. The engineer will be expected to own problem spaces end-to-end, contributing to system design, architecture decisions, and hands-on development.The environment consists of a fragmented ecosystem of 50+ legacy and internally built applications, requiring strong system thinking, data handling experience, and the ability to operate in ambiguity.Day-to-Day Responsibilities:The Senior Java Engineer will focus on designing and building scalable backend systems while driving modernization efforts across a complex application landscape.A significant portion of the role involves analyzing, decomposing, and re-architecting legacy systems, including migrating workloads to AWS (EC2, RDS) and improving overall system performance, reliability, and maintainability.They will build services responsible for data ingestion, transformation, validation, and distribution, working with data-heavy workflows (including market data).The engineer will also play a key role in system design and architecture, making pragmatic tradeoffs (e.G., scalability vs simplicity) and ensuring solutions are production-ready.Additional responsibilities include troubleshooting complex production issues (e.G., memory leaks, concurrency issues, latency bottlenecks), implementing observability practices (logging, metrics, tracing), and building resilient systems (retries, failure handling,



circuit breakers).The remaining portion of the role includes collaborating with engineers and stakeholders, helping clarify ambiguous requirements, shaping solutions, and providing technical leadership through code reviews and mentorship.Must-Haves:8-10+ years of experience as a Java Backend EngineerStrong expertise in Core Java (collections, concurrency, JVM internals, memory model)Experience with performance tuning, garbage collection, and profilingHands-on experience with Spring (Boot, MVC, Data) and Hibernate/JPAStrong system design and distributed systems knowledge (caching, messaging, eventual consistency)Experience with AWS or cloud-based architecturesStrong SQL and data handling experienceProven ability to troubleshoot complex production issuesExperience building systems beyond straightforward CRUD APIs (data pipelines, processing systems, etc.)Ability to operate in ambiguity and define solutions—not just execute tasksPlusses:Experience with data-intensive systems or data pipelinesExposure to microservices architecture (Spring ecosystem)Background in capital markets / financial servicesExperience modernizing or replacing legacy systems at scaleFamiliarity with CI/CD pipelines and DevOps practicesWe may use AI-enabled and/or automated tools to support parts of our recruitment process, including application screening, interview scheduling, and candidate communications. These tools are used to enhance consistency and efficiency. All hiring decisions involve human review and are not based solely on automated processing.The Company offers a total rewards package in accordance with all applicable federal, provincial, and local laws and requirements. Benefit eligibility and offerings vary based on role, employment status, and work location. For contractor positions, benefits are limited to those entitlements and protections required by applicable law, which may include (as applicable) vacation pay, public holidays, leaves of absence, and other legally mandated benefits or payments.#J-18808-Ljbffr

📌 Java Software Engineer (Toronto)
🏢 Collabera
📍 Toronto