About the job
Join Us at Gapstars
At Gapstars, we collaborate with Europe's most innovative tech companies, from groundbreaking startups to rapidly growing scaleups. Our mission is to assemble high-performing remote engineering teams that tackle real-world challenges with cutting-edge technologies. With our headquarters in the Netherlands and talent hubs in Sri Lanka and Portugal, we boast a vibrant community of over 275 engineers dedicated to delivering impactful solutions across various domains such as networking, marketplaces, SaaS, and AI. If you seek an environment that fosters technical excellence, a robust culture, and opportunities for growth, Gapstars is the place for you.
About the Position
We are in search of a hands-on Senior Java Developer (ATL/TL level) to take the reins of a complex legacy Java application landscape, currently operating on approximately 20 servers. This environment incorporates an older version of GlassFish and lacks sufficient documentation. Your primary challenge will be to understand, document, and maintain application-level integrations, stabilize the platform, and lay the groundwork for future modernization and migrations.
This role emphasizes development and integration ownership rather than operations, requiring a strong focus on technical discovery, documentation, and stewardship of legacy platforms.
Key Responsibilities
- Take ownership of a legacy Java platform from both an application and integration perspective.
- Discover, map, and document application dependencies, integration points, data flows, interfaces, deployment topology, and key runtime/config assumptions.
- Analyze and resolve complex production issues related to Java application behavior, performance bottlenecks, runtime issues, integration failures, and stability concerns.
- Gain familiarity and build confidence in the legacy runtime environment, including GlassFish configuration and deployments.
- Enhance maintainability through clear technical documentation, diagrams, runbooks, improved logging/observability, and incremental refactoring when appropriate.
- Support and guide engineering standards as an ATL/TL profile through code reviews, mentoring, and providing technical guidance on integration design and legacy-safe improvements.
- Collaborate closely with stakeholders to foster a shared understanding of the platform's architecture and future direction.

