Freelance Software Developer (Java) - Quality Assurance (AI Trainer)

Bachelor's or Master’s Degree in Computer Science, Software Engineering, Software Development, Computer Engineering, Mobile App Development, Cloud Computing, Data Science, Big Data or other related fields At least 3 years of professional experience in Java 17+ Advanced (C1) or above level of English Hands-on experience with JUnit 5, TestNG, Mockito, and TestContainers Proficiency with build tools (Maven, Gradle), IDEs (IntelliJ IDEA), and CI/CD pipelines (Jenkins, GitHub Actions, GitLab CI) Experience with the Spring ecosystem (Spring Boot, Spring Data, Spring Security), JPA/Hibernate Strong understanding of JVM internals, garbage collection, performance optimization, and design patterns Experience with messaging systems (Kafka, RabbitMQ) and microservices architectures Practical use of AI-assisted tools for refactoring, performance analysis, and test generation Familiarity with cloud platforms (AWS, Azure), containers, and Kubernetes Strong skills in JVM profiling (JProfiler, VisualVM) and debugging Ready to learn new methods, able to switch between tasks and topics quickly Work with challenging, complex guidelines Residing in Spain

Code generation and code review Prompt evaluation and complex data annotation Training and evaluation of large language models Benchmarking and agent-based code execution in sandboxed environments Working across multiple programming languages Adapting guidelines for new domains and use cases Following project-specific rubrics and requirements Collaborating with project leads, solution engineers, and supply managers