Senior Java Engineer L2 - Core Java, Concurrency & JVM

About the role

A large-scale financial services platform is looking for a Senior Java Engineer to join its active Java modernization journey. You will help migrate and evolve legacy systems toward modern Java (17/21) and cloud-native architectures on AWS, working on performance-critical, secure and highly scalable services running in production.

Key responsibilities

• Migrate legacy Java services to modern Java versions (Java 17 / Java 21)
• Refactor existing codebases to improve scalability, performance and maintainability
• Contribute to architectural evolution toward modern, cloud-native patterns
• Design and enhance high-performance backend systems for new features and platform evolution
• Collaborate directly with senior client stakeholders in a highly autonomous, client-facing environment
• Participate in production-related activities while keeping development and modernization as the main focus

Required profile

• Strong hands-on experience with Java in enterprise-scale systems, ideally in regulated or high-availability environments
• Proven experience with modern Java versions (Java 17 and Java 21)
• Experience modernizing enterprise Java platforms in financial or regulated industries
• Background designing high-throughput, secure, event-driven backend systems
• Comfortable explaining technical decisions to senior stakeholders; client-facing experience is a plus

Required skills

• Core Java: Collections Framework, object-oriented principles, design patterns, concurrency and multithreading (ExecutorService, thread pools, synchronization)
• REST APIs, HTTP methods, status codes, idempotency, API versioning and error handling
• Security: authentication and authorization with Spring Security, OAuth and JWT
• JVM analysis and tuning: memory management, garbage collection, thread dumps, JConsole, JVisualVM, JMX
• Debugging: local and remote debugging, structured debugging approaches
• Maven, NoSQL (MongoDB preferred), event-driven architectures (Kafka or similar)
• Unix/Linux basics and AWS (strong plus); multi-cloud or hybrid cloud exposure is a bonus