Senior/ Mid Java Backend Engineer Spring Boot/Oracle

We are re-platforming a national public-sector system in the EU: -750 screens of a legacy client-server 4GL, rebuilt as a modern Spring Boot / Spring Modulith application - on top of an Oracle database whose PL/SQL API is contractually frozen.

You will build real modules of that system. The architecture, module contracts, and transaction rules are set by our tech lead and senior engineers - your job is to deliver features inside those boundaries, at production quality, on a system that a whole country depends on.

This is a rare place to grow: modern Java on one side, deep Oracle work on the other, with senior engineers reviewing your code every week. You don't need to be an Oracle expert on day one - you need to want to become one.

What you will do

• Build features end-to-end inside a module - from REST API through the domain layer down to the Oracle call, with module boundaries enforced automatically in CI.
• Write and maintain PL/SQL adapters - implement typesafe adapters against Oracle packages using patterns the team has defined (jOOQ codegen), so the domain layer never sees JDBC or PL/SQL types.
• Write the tests that make the migration safe - module tests and integration tests against a real Oracle database; on this project, "it works on my machine" is not a category.
• Fix what the legacy system reveals - investigate behaviour of the old application, reproduce it, and make the new code match it exactly.
• Take part in code review - both receiving it from seniors and reviewing your peers' work.

What we expect (must-have)

• Solid Java and Spring Boot in production - at least 3-5 years actually building and shipping Spring services, not just maintaining them
• Real SQL skills, and comfort going into the database - you write non-trivial queries yourself, you can read a stored procedure and reason about what it does, and you're not afraid of an execution plan
• Testing as a habit - you write tests without being asked, and you've worked with CI
• Strong skills with AI coding tools - Claude (Claude Code) or Codex - you use them daily and effectively for coding, refactoring, and reviewing; we work AI-first and expect you to multiply your output with them
• Working English - you can read specs, write clear commit messages and comments, and hold a technical discussion in an international team
• Appetite for the hard part - this project runs on legacy Oracle logic; the engineers who thrive here are the ones curious about how the old system works, not the ones waiting for a clean greenfield ticket

Nice to have

• PL/SQL beyond calling it - writing packages, understanding transactions and locking
• jOOQ, or any codegen against database contracts
• Keycloak or OAuth2/OIDC integration
• Spring Batch, or large-scale batch processing
• Kubernetes / OpenShift
• Some React - useful when your module meets the frontend lane
• Exposure to legacy modernization, banking, telco, insurance, or public-sector systems

8seneca is committed to building a workplace where employees can grow, contribute, and thrive.

1. Engaging perks and benefits for your well-being

We offer a competitive package including 13th-month salary, on-time salary payments, and project bonuses based on revenue. Employees are fully covered with 100% salary-based insurance, advanced healthcare insurance, annual health check-ups, and Tet/holiday gifts.

Work-life balance is supported with 14 days annual leave plus 3 Christmas days, flexible working arrangements (3 days WFH for senior lever up), modern office facilities, team-building trips (4D3N at 5-star resorts), and wellness support such as vitamins in the office. In addition, the office provides coffee machines, snacks, and fresh fruits to support daily comfort and energy.

2. World-class technology and impactful projects

You will work with modern technologies in AI, Data, Cloud, and Software Engineering on large-scale international projects for European clients, including strategic initiatives for our company-one of the top IT companies in Europe. We also provide access to modern AI tools like ChatGPT and Claude Code to support productivity and engineering excellence.

3. A culture of growth, collaboration, and learning

We foster continuous learning through mentorship programs, 1-1 feedback, and performance reviews. Employees are empowered to take ownership, make decisions, and learn from mistakes in a safe, supportive environment. A shared company library also promotes continuous self-development.

At 8seneca, you will work with talented people from diverse backgrounds, united by a passion for technology and innovation.