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Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Senior Java Developer - **Company:** UST España - **Location:** Ferrol, Spain (Remote available) - **Contract:** Permanent contract - **Skills:** Java (Programming Language), Application Programming Interfaces (APIs), Amazon Web Services, Amazon S3, X86-64, Apache HTTP Server, Automation of Tests, Cloud Computing, Cloud Engineering, Continuous Integration, Data Stores, Software Debugging, Linux, Digital Technology, Distributed Systems, Github, Protocol Buffers, Identity and Access Management, Internetworking, Spring Framework, Junit, Python (Programming Language), PostgreSQL, MongoDB, Pattern Recognition, Redis, Mockito, Rxjava, Delivery Pipeline, Spring-boot, Backend, Event Driven Architecture, Containerization, Integration Tests, Apache Kafka, Reactive Programming, Teamcity - **Published:** August 26, 2026 - **Apply:** https://www.buscojobs.com.es/senior-java-developer-en-ferrol-ID-369020153 ## About the Role 8+ years of professional experience with Java development. ~3+ years of hands-on experience with Java 17 or Java 21, including modern language features such as records, sealed classes, pattern matching, and virtual threads when applicable. ~ Strong expertise in Spring Framework and Spring Boot in production environments. ~ Proven experience with reactive programming using Project Reactor or RxJava (Mono, Flux, backpressure, retry strategies, hot vs. Solid testing practices using JUnit 5, Mockito, and AssertJ. ~ Experience developing integration tests against real dependencies and contract/parity testing. ~ Strong knowledge of Kafka consumer and producer semantics. ~ Redis, PostgreSQL, or MongoDB. ~ Cloud experience with AWS (or equivalent cloud platforms), including services such as S3, IAM, managed Kafka solutions, and container runtimes. ~ English level C1 or higher. Knowledge of container packaging and multi-architecture image builds (Linux/AMD64 and Linux/ARM64). Python knowledge with the ability to read, understand, and debug existing code. Experience working with Apache Arrow or other columnar data formats. CI/CD pipeline ownership using TeamCity, GitHub Actions, or similar technologies. Numerous benefits (Health Care Plan, Internet Connectivity, Life and Accident Insurances). ~ Flexible Compensation Program: meals, kindergarten, transport, online English lessons, health care plan, and more. ## Description More in detail, UST is a multinational company based in North America, certified as a Top Employer and Great Place to Work company with over 35,000 employees worldwide and presence in more than 35 countries.We are leaders in digital technology services, providing large-scale technological solutions to some of the world's most renowned organizations.We are seeking a highly skilled Senior Java Developer with extensive experience building scalable, high-performance distributed systems.You will join a talented engineering team responsible for designing, developing, and evolving mission-critical applications using modern Java, cloud-native architectures, and event-driven technologies.? Design, develop, and maintain robust backend services using Java ***** and Spring Boot.Develop and maintain gRPC APIs and Protobuf schemas, ensuring backward compatibility and proper schema evolution.Work with Kafka-based event-driven architectures and production-scale data stores.Create and maintain automated testing suites, including unit, integration, and contract tests.Participate in troubleshooting, root cause analysis, and postmortem activities.Contribute to CI/CD pipelines, cloud infrastructure, and containerized deployments.8+ years of professional experience with Java development.~3+ years of hands-on experience with Java 17 or Java 21, including modern language features such as records, sealed classes, pattern matching, and virtual threads when applicable.~ Strong expertise in Spring Framework and Spring Boot in production environments.~ Proven experience with reactive programming using Project Reactor or RxJava (Mono, Flux, backpressure, retry strategies, hot vs. Solid testing practices using JUnit 5, Mockito, and AssertJ.~ Experience developing integration tests against real dependencies and contract/parity testing.~ Strong knowledge of Kafka consumer and producer semantics.~ Redis, PostgreSQL, or MongoDB.~ Cloud experience with AWS (or equivalent cloud platforms), including services such as S3, IAM, managed Kafka solutions, and container runtimes.~ English level C1 or higher.Knowledge of container packaging and multi-architecture image builds (Linux/AMD64 and Linux/ARM64).Python knowledge with the ability to read, understand, and debug existing code.Experience working with Apache Arrow or other columnar data formats.CI/CD pipeline ownership using TeamCity, GitHub Actions, or similar technologies.Numerous benefits (Health Care Plan, Internet Connectivity, Life and Accident Insurances).~ Flexible Compensation Program: meals, kindergarten, transport, online English lessons, health care plan, and more.~ Free access to several training platforms.~ Real Work-Life Balance measures (flexibility, remote work policy, summer schedule, and more).~ ## Related Videos - [Beam Me Up, Java! 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