Languages
Java, Python, TypeScript, JavaScript, SQL
Joseph R. O'Neil Jr.
Enterprise Application Architect | Legacy Modernization | AI-Assisted Software Engineering | Full-Stack Architecture
Lawrence, MA | josephroneil@gmail.com | 978-305-5241 | GitHub | LinkedIn
Enterprise Application Architect with more than 20 years of experience designing, modernizing, and delivering mission-critical enterprise applications across healthcare, finance, insurance, manufacturing, government, and defense. Expert in transforming undocumented legacy systems into modern platforms while preserving the business knowledge embedded within them.
Modernizes systems to solve business problems, not just to adopt new technology, and combines deep architecture experience with AI-assisted engineering to accelerate delivery without sacrificing quality.
Core Expertise
What I do best
Enterprise Application Modernization
Legacy System Reverse Engineering
Solution & Application Architecture
AI-Assisted Software Engineering
Spring Boot & Java Enterprise Development
Next.js / React / TypeScript
REST APIs & System Integration
Cloud & Container Platforms
Technical Leadership & Mentoring
Performance & Reliability Engineering
Architecture & Technical Documentation
Secure Enterprise Applications (OAuth2, JWT, Okta)
Technical Skills
Languages, frameworks, platforms
Frameworks
Spring Boot, Spring MVC, Grails, Hibernate/JPA, Next.js, React, Tailwind CSS
AI
Claude Code, OpenAI Codex, agentic development, prompt engineering, RAG, AI-assisted refactoring
Cloud & DevOps
AWS, Docker, Docker Compose, GitLab CI, ArgoCD, Kubernetes, CloudFormation
Databases
Oracle, PostgreSQL, SQL Server, DynamoDB, Supabase
Architecture
Microservices, REST APIs, OAuth2/JWT, event-driven systems, legacy modernization
Professional Experience
Selected roles
Technical Consultant, Intact (Contract through RWH Consulting Group)
- Modernizing enterprise Java applications with AI-assisted reverse engineering, implementation planning, and delivery.
- Architecting Spring Boot and Next.js solutions to replace legacy Struts systems while preserving existing business behavior.
- Developing modernization patterns, automated documentation, validation strategies, and reusable implementation frameworks.
- Building proof-of-concepts that demonstrate accelerated delivery using AI-assisted engineering workflows.
- Creating engineering laboratories to evaluate AI workflows, reliability, serialization, state management, and RAG architectures before production adoption.
Senior Developer, Medtronic (Contract through Populus Group)
- Designed Spring Boot microservices, Quartz scheduling, batch processing, and modern React/Next.js applications.
- Modernized legacy Grails and Spring applications while introducing reusable frontend components and secure APIs.
- Integrated Okta/Azure authentication, Oracle databases, Docker, GitLab CI, and ArgoCD deployment pipelines.
- Delivered enterprise applications as a solo developer using structured AI-assisted engineering.
Software Engineer, MIT Lincoln Laboratory (Contract through Digital Prospectors)
- Contributed to a classified artificial intelligence research program supporting mission-critical geospatial capabilities.
- Developed Java and JavaScript components for enterprise geospatial applications within a secure development environment.
- Designed Python data ingestion services to automate Excel processing and populate PostgreSQL databases.
- Built and maintained containerized development environments using Docker Compose and virtualized infrastructure.
- Produced technical documentation and collaborated with cross-functional engineering teams in an Agile process.
Senior Developer, Medtronic (Contract through Genesis 10)
- Contributed to enterprise modernization initiatives using Spring Boot, Next.js, React, and Tailwind CSS.
- Applied AI-assisted reverse engineering techniques to accelerate legacy system analysis, implementation planning, and test creation.
- Planned and executed framework modernization projects, upgrading multiple Grails applications and Java runtimes.
- Prepared enterprise applications for modern containerized deployment environments, including Kubernetes compatibility.
- Collaborated with cross-functional teams to preserve existing business functionality while improving maintainability.
Tech Lead, LPL Financial (Contract-to-Hire through DYSIS)
- Served as technical lead across multiple enterprise modernization initiatives supporting Trade Resiliency, Batch Processing, and BODS.
- Led technical discovery, research, and reverse engineering of existing batch environments, business domains, and enterprise data flows.
- Partnered with stakeholders to define scope, decompose work into Jira epics and stories, and guide implementation priorities.
- Produced architecture documentation, ER diagrams, and system models using PlantUML.
- Developed Python utilities to generate database artifacts and streamline migration activities from architectural models and Excel-based sources.
Application Architect, Mapfre Insurance
- Supported multi-line insurance quoting platforms using ACORD XML, Spring, RabbitMQ, and REST integrations.
- Built a RabbitMQ Spring Boot API wrapper prototype and a React-based SSO landing experience.
- Diagnosed Webscan findings and applied secure coding remediations.
Java Developer, MIT Lincoln Laboratory
- Developed Spring Boot microservices deployed on hardened RHEL EC2 containers.
- Migrated Spring MVC applications, transitioned security configuration to annotations, and introduced JUnit test coverage.
- Automated infrastructure through CloudFormation, Ansible, and centralized logging pipelines.
Senior Programmer, SGT | Volpe Center
- Built Safercar.gov's Manufacturer Portal using Spring Cloud microservices, AWS Lambda, and Angular 5.
- Refactored legacy ColdFusion and Struts2 workloads into Spring Boot services with EHCache and schedulers.
- Championed modern tech stacks, CI/CD automation, and OAuth2 security patterns.
Application Architect, Accenture
- Delivered Pega-based insurance and government identity solutions with bespoke Java extensions and localization.
- Mentored global teams, authored technical design documentation, and managed cloud administration for Pega environments.
- Completed Accenture Technical Architecture School to deepen enterprise architecture leadership.
Senior Software Engineer, Harvard Medical School
- Directed enhancements to Harvard Catalyst and Grant Central platforms while mentoring distributed teams.
- Optimized MySQL performance and led refactoring using MVC, DTO, and Delegate patterns.
- Rebuilt the Grant Central build pipeline for repeatable releases.
Senior Web Developer, Converge
- Modernized enterprise Java applications by refactoring legacy Struts, JSP, and EJB systems into Spring, iBATIS, JSF, and Facelets-based architectures.
- Evaluated and introduced emerging open-source technologies, including Hibernate, Struts 2, Tapestry, FreeMarker, and EJB3, to establish a more maintainable and extensible application framework.
- Designed reusable framework components including validators, converters, partial-page rendering, and rich user interface components.
- Supported enterprise J2EE, VB6, and VB.NET applications while producing functional and technical design documentation.
- Managed enterprise application deployments across JBoss and Tomcat environments.
System Analyst, Accenture
- Contributed to enterprise Model N implementations by translating functional requirements into technical designs and customizing Java/J2EE applications.
- Extended Java, XML, and ORM components while supporting enterprise enhancements and application integration.
- Served as Accenture Site Lead and Java Capabilities Lead for the Boston area.
Software Engineer Consultant, Fidelity Investments
- Enhanced enterprise Java/J2EE frameworks, batch processing, and database components supporting large-scale financial applications.
- Developed and maintained JavaBeans, Enterprise JavaBeans, Sybase stored procedures, and WebLogic-based applications.
- Supported enterprise application troubleshooting across Java and C/C++ components.
Independent Software Consultant, Self-Employed
- Developed custom web applications and database-driven websites for small businesses, nonprofit organizations, and startup clients using Java, JSP/Struts, PHP, and MySQL.
- Designed and deployed dynamic web solutions while expanding expertise in enterprise Java technologies and modern web development.
- Completed advanced professional development in Unix system administration, networking, and C# through Worcester Polytechnic Institute.
Software Engineer, Davox Corporation (now Concerto Software)
- Maintained and enhanced enterprise PowerBuilder/Sybase call center software while contributing to next-generation Java/J2EE research and development.
- Developed Java technologies including JSP, Servlets, EJBs, XML/XSLT, and Tomcat supporting future enterprise platform initiatives.
- Led migration of more than 80 enterprise applications across multiple PowerBuilder versions, establishing repeatable conversion processes and documentation.
- Resolved hundreds of production defects and enhancements across large-scale enterprise applications.
Manufacturing Engineer / Software Developer, Raytheon
- Designed and built the Raytheon Labor Standard Estimator, a client-server manufacturing application with an Oracle backend that automated labor standards management and supported manufacturing process planning.
- Replaced a commercial labor standards system with an internally developed solution, generating over $400,000 in annual savings.
- Reduced proposal preparation time by 80 percent and labor standards development time by 60 percent through process automation.
- Automated labor standards calculations, engineering reporting, and Six Sigma opportunity analysis, improving engineering productivity and process consistency.
- Consolidated four DOS engineering applications into a single Windows application and designed an intuitive user interface that significantly reduced user training time.
- Designed the Oracle database architecture and enterprise application foundation for the Labor Standard Estimator, creating a system that continued in production for more than a decade after my departure.
Selected Projects
AI engineering projects and architecture labs
KnowledgeVault AI
AI-powered document management and RAG platform.
QueryLite
Natural-language analytics and SQL exploration platform.
Reliability Lab Dashboard
Reliability, serialization, and state-management labs for evaluating system behavior.
Modernization research
Practical AI engineering patterns, architectural tradeoffs, and modernization techniques.
Education
Foundations
University of Lowell
B.S. Mechanical Engineering Technology
Northern Essex Community College
A.S. Engineering Science
Additional professional education
Accenture Technical Architecture School, Worcester Polytechnic Institute, and Boston University.