Java engineer Jobs in San Mateo, CA

As a Senior Java Engineer, you will work remotely on an hourly paid basis to review AI-generated Java code, architectural solutions, and technical explanations, as well as generate high-quality reference implementations and reasoning steps. You will assess solutions for accuracy, clarity, and adherence to the prompt; identify errors in logic, performance, or design; fact-check technical information; write high-quality explanations and model solutions that demonstrate correct methods; and rate and compare multiple AI responses based on correctness and reasoning quality.

This fully remote, hourly paid contractor role is with SME Careers, a fast-growing AI data services company and subsidiary of SuperAnnotate that provides AI training data to many of the world’s largest AI companies and foundation model labs, where your Java expertise will directly help improve the world’s premier AI models.

Key Responsibilities :

• Develop AI Training Content : Create detailed prompts in various topics and responses to guide AI learning, ensuring the models reflect a comprehensive understanding of diverse subjects.
• Optimize AI Performance : Evaluate and rank AI responses to enhance the model's accuracy, fluency, and contextual relevance.
• Ensure Model Integrity : Test AI models for potential inaccuracies or biases, validating their reliability across use cases.

Your Profile :

• Bachelor’s degree or higher in Computer Science, Software Engineering, or a closely related technical field.
• 5+ years of professional software engineering experience, with significant hands-on work in Java on production systems.
• Deep understanding of core Java, concurrency primitives, and the Java Collections Framework.
• Extensive experience building and maintaining backend services using Spring or Spring Boot, REST APIs, and microservice architectures.
• Strong grasp of software design principles, system design, and performance optimization in distributed Java systems.
• Minimum C1 English proficiency (written and spoken), with the ability to write clear technical explanations and follow detailed English-language guidelines.
• Comfort working with modern engineering tooling such as Git, CI / CD pipelines, automated testing frameworks, and containerization technologies.
• Demonstrated experience conducting thorough code reviews and providing structured, constructive feedback to other engineers.
• Previous experience with AI data training, annotation, or evaluating AI-generated technical content is a strong plus.
• Highly detail-oriented and systematic, with a methodical approach to evaluating reasoning quality and identifying subtle issues in Java solutions.