Principal Java Engineer (Technical Lead)

freeC's Client

• Design, implement, and maintain complex features for large-scale web applications using Java
• Lead technical investigations and solve challenging issues related to performance, scalability, maintainability, and legacy systems
• Take ownership of critical technical tasks, define implementation approaches, and document solutions for long-term reuse
• Lead technical design and support development members from a technical perspective
• Perform code reviews and improve code quality, coding standards, and maintainability
• Improve existing systems through refactoring, optimization, version upgrades, and modernization initiatives
• Utilize AI tools (GitHub Copilot, ChatGPT, Claude, Gemini, etc.) to improve development productivity and test automation

Requirements:

• 10+ years of experience in Java web application development
• At least 2 years of experience in a technical leadership role such as Technical Lead, Solution Architect, Technical Architect, or equivalent
• Strong experience developing and maintaining large-scale or high-traffic web systems
• Strong understanding of scalable architecture, maintainability, performance optimization, and long-term system operation
• Hands-on experience with refactoring, code review, unit testing, SQL optimization, and legacy system modernization
• Experience leading technical design and solving complex system-level issues
• Strong experience with:
• Java
• JavaScript, jQuery
• PostgreSQL, MySQL
• Frameworks such as Spring, Spring Boot, Struts, Seasar2, Hibernate
• Experience with automation testing tools such as JMeter, JUnit, Selenium
• Experience with DevOps tools such as Git, GitHub, Jenkins, Docker
• Ability to create technical documentation and communicate technical solutions clearly
• Strong problem-solving, analytical thinking, and research skills
• Experience working with Japanese projects/companies
• Practical experience using AI development tools

• 13th and 14th-month salary; full social insurance contributions based on gross salary
• 100% salary during probation
• Opportunities to attend training in Japan
• Japanese engineers provide on-the-job training (OJT)
• Full social insurance based on contract salary
• Annual company trip, with 50% of the cost covered for employees’ families
• Many events throughout the year: Women’s Day, Men’s Day, Children’s Day, Mid-Autumn Festival, Christmas, Year-End Party, quarterly teambuilding, family activities, monthly birthday celebrations...
• Annual health checkups