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.Job responsibilities:• Perform a technical upgrade of the banking application, including:• Analyze existing application architecture, dependencies, and configurations to identify upgrade impacts.• Refactor and optimize code as needed to ensure compatibility with new versions.• Collaborate with architects, QA, and DevOps teams to ensure smooth integration, testing, and deployment.• Document upgrade steps, migration guidelines, and technical challenges/resolutions.• Support knowledge transfer and provide 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 1pm ET (7pm CET) occasionally and as neededNice-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.Our attractive offer contains:• Work from our office in Warsaw/Wroclaw/Torun• 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• Rewarded referral program, minimum PLN 6k for recommendation• 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