System One · 4 hours ago
Senior Java Application Developer (onsite)
Washington, DC
Contract
Onsite
Senior LevelSystem One is a leading provider of outsourced services and workforce solutions across North America. They are seeking a Senior Java Application Developer to support the modernization of legacy systems by upgrading them from Java/JDK 8 to Java/JDK 21, while also ensuring smooth operations and maintenance of these systems.
Staffing Agency
No H1B
Security Clearance RequiredU.S. Citizen Only
Responsibilities
Support up to 3 legacy mission-essential systems in the upgrade from Java/JDK 8 to Java/JDK 21 technology and beyond with operations and maintenance
Leverage knowledge of Object-Oriented Programming, software development methodologies, and the Java language to seamlessly transition systems to the desired version
Ensure smooth and successful migration using expertise in technologies such as Servlet, JSP, Tag Library, JavaBean, and SQL Server database
Modernize the user interface and enhance overall user experience using tools like Maven, JavaScript, jQuery, Knockout.js, HTML, and CSS
Be well-versed in Windows authentication, SSL, session management, and Single Sign-On (SSO) technologies
Familiarity with RESTful web services, JSON parsing, and multipart/form-data file management is highly valued
Experience successfully migrating Java applications across multiple major versions
Knowledge of common pitfalls and solutions when upgrading Java applications
Understanding of deprecated features and their modern replacements
Experience identifying and resolving compatibility issues
Proficiency with build tools (Maven/Gradle)
Experience updating build pipelines to accommodate newer Java versions
Dependency management skills and handling library compatibility challenges
Experience with continuous integration/continuous deployment (CI/CD) pipelines (Azure DevOps, GitLab)
Experience with application performance monitoring tools and techniques
Knowledge of log management and analysis systems
Ability to create and maintain runbooks for operational procedures
Proficiency in identifying and resolving production issues
Understanding of JVM tuning and garbage collection optimization
Experience implementing and maintaining automated health checks
Knowledge of security patch management and vulnerability assessment
Version control with Git
Familiarity with application servers (e.g., Tomcat, WebSphere, WildFly)
Knowledge of common enterprise integrations (SQL Server databases, messaging systems)
Experience with containerization technologies (Docker, Kubernetes) is a plus
Excellent written and verbal communication skills
Strong problem-solving abilities and attention to detail
Ability to document migration processes, decisions, and technical debt
Self-motivated with the ability to work independently
Collaborative approach when working with existing development teams
Strong time management skills to deliver migration within schedule constraints
Experience providing on-call support and incident management
Qualification
Required
US citizenship required per government contract
Must be able to obtain Public Trust clearance
Java experience
Strong aptitude in modernizing systems
Support up to 3 legacy mission-essential systems in the upgrade from Java/JDK 8 to Java/JDK 21 technology and beyond
Expertise in technologies such as Servlet, JSP, Tag Library, JavaBean, and SQL Server database
Proficiency in tools like Maven, JavaScript, jQuery, Knockout.js, HTML, and CSS
Well-versed in Windows authentication, SSL, session management, and Single Sign-On (SSO) technologies
Familiarity with Spring, Spring MVC, and ORM technologies like Hibernate and JPA
Familiarity with RESTful web services, JSON parsing, and multipart/form-data file management
Expertise in vulnerability remediation techniques such as CSRF, SQL injection, XSS, and reflection attacks
Previous experience successfully migrating Java applications across multiple major versions
Knowledge of common pitfalls and solutions when upgrading Java applications
Understanding of deprecated features and their modern replacements
Experience identifying and resolving compatibility issues
Proficiency with build tools (Maven/Gradle)
Experience updating build pipelines to accommodate newer Java versions
Dependency management skills and handling library compatibility challenges
Experience with continuous integration/continuous deployment (CI/CD) pipelines (Azure DevOps, GitLab)
Experience with application performance monitoring tools and techniques
Knowledge of log management and analysis systems
Ability to create and maintain runbooks for operational procedures
Proficiency in identifying and resolving production issues
Understanding of JVM tuning and garbage collection optimization
Experience implementing and maintaining automated health checks
Knowledge of security patch management and vulnerability assessment
Version control with Git
Familiarity with application servers (e.g., Tomcat, WebSphere, WildFly)
Knowledge of common enterprise integrations (SQL Server databases, messaging systems)
Excellent written and verbal communication skills
Strong problem-solving abilities and attention to detail
Ability to document migration processes, decisions, and technical debt
Self-motivated with the ability to work independently
Collaborative approach when working with existing development teams
Strong time management skills to deliver migration within schedule constraints
Experience providing on-call support and incident management
Preferred
Experience with containerization technologies (Docker, Kubernetes) is a plus
Benefits
Health and welfare benefits coverage options including medical, dental, vision, spending accounts, life insurance, voluntary plans
Participation in a 401(k) plan
Company
System One
System One is a professional staffing firms.
Founded in 2008
5001-10000 employees
Funding
Current Stage
Late StageTotal Funding
$301.8MKey Investors
TruistOaktree Capital ManagementProspect Capital Corporation
2021-01-28Debt Financing· $290M
2020-12-08Private Equity
2016-09-20Acquired
Leadership Team
Troy Gregory
Chief Executive Officer
Dan Moran
Chief Financial Officer
Recent News
2026-01-06
Company data provided by crunchbase