Senior Java Backend Developer

We are seeking an experienced Senior Java EE Developer to join our consulting team for a high-impact modernization and upgrade project within a mission-critical banking system. The role focuses on upgrading and stabilizing an existing Java Enterprise (Java EE / JEE) application, including components based on Enterprise JavaBeans (EJB), application servers, and persistence layers. The ideal candidate has hands-on experience with Java EE technologies, including EJB, and has actively participated in technical upgrades or migrations of large-scale enterprise systems, rather than only greenfield development. Remote work within Poland, with the option to work from CGI offices in multiple cities. Job responsibilities: Perform a technical upgrade of the banking application, including: • Analyzing the existing application architecture, dependencies, and configurations to identify upgrade impacts. • Refactoring and optimizing code as needed to ensure compatibility with new versions. • Collaborating with architects, QA, and DevOps teams to ensure smooth integration, testing, and deployment. • Documenting upgrade steps, migration guidelines, and technical challenges/resolutions. • Supporting knowledge transfer and providing guidance to client technical teams post-upgrade. Required qualifications to be successful in this role: • 5+ years of Java development experience in enterprise environments. • Hands-on experience with Java EE / Jakarta EE technologies, including Enterprise JavaBeans (EJB) and application servers (e.g., JBoss/WildFly, WebLogic, WebSphere). • Proven experience with application upgrade/migration projects in large-scale, mission-critical systems. • Solid understanding of enterprise integration patterns, deployment pipelines, and performance tuning. • Strong problem-solving and debugging skills. • Experience in the banking or financial services industry is a plus. • Flexibility to work until 1:00 PM ET / 7:00 PM CET occasionally and as needed. Nice to Have Skills: • Familiarity with JPA specifications and persistence migration best practices. • Exposure to containerization and cloud platforms (e.g., OpenShift, Kubernetes, AWS, Azure). • Knowledge of CI/CD pipelines and modern DevOps practices. • Strong communication and consulting skills for client-facing interactions. • Experience with AI tools. • Knowledge of database performance. • Knowledge of security. • Experience with website load/performance tools and best practices related to performance parameters and metrics. • Java upgrade experience. • Experience with monolith decomposition into microservices. • Architecture skills. What we offer: • Healthcare / Medicover paid by CGI with a free dental package • Share purchase plan co-financed by CGI, with the possibility of cashing at any time • Sport card • Employee psychological support program • Annual bonus plan, depending on the annual financial results • Referral program with a reward of PLN 6,000 for each successful referral • Be Consultant program, thanks to which you have the opportunity to strengthen your competences • Mentoring program • Possibility of accounting for creative work (author's tax-deductible costs) • Attractive training program - Brown Bags, hackathons and knowledge sharing • Additional insurance - life, accident and serious illness insurance • Additional childbirth insurance