Senior Full Stack Java Developer

Cloud and Things; Alexandria (VA); On-site; USD 166,000 - 187,000; Full time

Job summary

Cloud and Things is seeking a Senior Full Stack Java Developer to lead and contribute to a large legacy Java application in Northern Virginia. Expect hands-on work across server-side Java and modern frontend, with mentoring responsibilities for junior developers and collaboration with business analysts and architects.

The role emphasizes reverse-engineering undocumented code, using AI-assisted development tools, and contributing to agentic AI initiatives.

Qualifications

• 7+ years of professional Java development experience with senior/lead responsibilities.
• Strong full-stack capability with server-side Java and modern frontend (JS/TS, Angular or React).
• Experience reading and reconstructing undocumented legacy code.
• Hands-on experience with AI-assisted development tools.
• Mentoring or leading less-experienced developers.
• Willingness to work onsite in Northern Virginia.

Responsibilities

• Write, review, and maintain production Java and frontend code.
• Analyze existing full-stack codebases, architecture, and workflows.
• Reverse-engineer legacy code and document interfaces.
• Troubleshoot defects and deliver fixes with minimal disruption.
• Use AI-assisted tools to accelerate development and modernization.
• Mentor junior developers and provide technical guidance.

Skills

Java development

Full-stack

Frontend (Angular/React)

AI-assisted development tools

Legacy code understanding

Mentoring/leadership

Onsite collaboration

Onsite client work

Education

Bachelor's degree in CS/IT/Engineering

Tools

Spring / Spring Boot

SQL

REST APIs

Job description

Back Senior Full Stack Java Developer

Other Area(s) Alexandria, Virginia W-2 hourly Sep 8, 2026

*This is an exempt position. Salarycommensuratewith experience*

Job Title:

• Senior Full Stack Java Developer

Location:

• Fairfax County / Alexandria, VA (Onsite)

Duration:

• 6 months (with potential for extension)

Start Date:

• Estimated - 10/1/26

W2 Hourly Rate:

• $80-$90/hour

Application Deadline:

• 9/10/26

We are seeking a Senior Full Stack Java Developer who will support our public sector K-12 education client in Northern Virginia. This hands-on lead will work daily in a large, mission-critical legacy Java application, reverse-engineer sparsely documented code, delivering enhancements and fixes, and mentoring junior developers within the client's established architecture. The role also uses AI-assisted development tools and is expected to contribute to future agentic AI development initiatives.

Duties

• Write, review, enhance, and maintain production code across server-side Java and front-end application components.
• Analyze existing full-stack Java codebases, application architecture, integrations, dependencies, and technical workflows.
• Reverse-engineer and document complex legacy code, including undocumented functionality, interfaces, and architecture.
• Troubleshoot defects and technical issues, identify root causes, and deliver fixes while minimizing disruption to existing functionality.
• Use AI-assisted development tools, including AI coding assistants and copilots, to accelerate analysis, development, troubleshooting, and modernization.
• Contribute to initiatives that design and build AI agents and agentic workflows for software development and application modernization.
• Mentor junior developers through code reviews, pair programming, technical guidance, and knowledge sharing.
• Provide day-to-day technical leadership within the client's established architecture and development framework.
• Identify and implement opportunities to improve code quality, maintainability, performance, reliability, refactoring, and modernization.
• Collaborate with business analysts, developers, architects, and technical teams to translate requirements into technical solutions.
• Create and maintain technical documentation covering application functionality, architecture, interfaces, dependencies, and workflows.
• Support testing, debugging, deployment, and production troubleshooting activities.
• Work onsite with the client team in the Fairfax County / Alexandria, Virginia area.

Mandatory Qualifications

• 7+ years of professional Java development experience, including senior-or-lead-level responsibility.
• Strong full-stack development capability with server-side Java and hands-on modern front-end experience using JavaScript or TypeScript with a framework such as Angular or React.
• Demonstrated experience reading, understanding, and dissecting existing or legacy code and rapidly reconstructing undocumented architecture.
• Hands-on proficiency with AI-assisted development tools, including AI coding assistants or copilots.
• Experience analyzing application architecture, dependencies, integrations, and technical workflows.
• Strong object-oriented programming knowledge and core Java development principles.
• Experience mentoring or providing technical guidance to less-experienced developers.
• Experience supporting legacy applications with limited or outdated documentation.
• Experience troubleshooting and enhancing existing applications, not exclusively building new applications.
• Strong analytical, problem-solving, communication, and collaboration skills, including comfort working onsite with a client team.
• Must be local to Northern Virginia or willing to relocate or commute for onsite work.

Desirable Qualifications

• Experience building applications and systems in the education domain.
• Hands-on experience building AI agents and agentic workflows, or demonstrable depth with agentic AI and coding tools with the ability to grow into agent-focused development.
• Experience integrating large language models into applications or development pipelines, including prompt engineering, retrieval, and tool or function calling.
• Enthusiasm for staying current with AI-assisted software development practices.
• Experience with Java/JEE enterprise applications.
• Experience with Spring or Spring Boot, REST APIs, and web services.
• Experience with relational databases and SQL.
• Experience with application servers and enterprise integration technologies.
• Experience working with large, complex, mission-critical applications.
• Experience with code analysis, refactoring, modernization, or migration initiatives.
• Experience in government, public sector, education, healthcare, financial services, or other highly regulated environments.

Educational & Certification Requirements

• Bachelor's degree in Computer Science, Information Technology, Engineering, or a related field, or equivalent experience.

Ready to make a difference?

We’re eager to connect with qualified candidates committed to delivering results and fostering excellence within client projects.

Cloud and Things complies with all applicable federal, state, and local laws regarding recruitment and hiring. All qualified applicants are considered for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, age, disability, protected veteran status, or any other category protected by applicable federal, state, or local laws.