Senior Java Developer Application Support & Development

The AES Group•Decatur, IL

6d•Onsite

About The Position

The Senior Java Developer will provide production support and application maintenance for existing Java-based enterprise applications in the manufacturing and industrial technology sector. The role is approximately 80% production support and 20% development, with the balance depending on business priorities and incident volume. Responsibilities also include Java development and enhancements, security remediation, and integration-related work as business needs evolve. The developer should be able to navigate legacy code, investigate unfamiliar application behavior, and resolve technical issues, including in environments with limited documentation. This is a fully on-site position at a client office five days per week in Decatur, Illinois (preferred), or East Peoria, Illinois. A split arrangement between the offices may be possible subject to business requirements; remote work is not available. Candidates who are considering relocation may be evaluated if they can relocate promptly and meet the on-site requirement from their first day. The role involves responding to production issues raised through ticketing systems, email, phone, Microsoft Teams, and direct user requests, and coordinating with other teams when issues fall outside the application's scope. The anticipated engagement duration is approximately six months and is subject to budget availability and leadership approval. The developer will provide application support and development capacity while the existing technical lead focuses on an automated storage and retrieval system (ASRS) integration initiative. A bachelor's or master's degree is not mandatory; candidates with an associate degree or equivalent relevant experience may be considered based on their technical skills and practical experience.

Requirements

Approximately 3–7 years of hands-on Java development experience, with at least 3 years preferred as a minimum.
Strong practical experience with Java 8, particularly in enterprise, production, and legacy application environments.
Hands-on experience with Spring MVC and full-stack Java applications, including backend and frontend application logic.
Strong SQL skills and practical experience working with Oracle databases.
Significant experience in production application support, incident management, troubleshooting, and defect resolution.
Demonstrated ability to investigate unfamiliar code, perform root-cause analysis, and resolve issues independently.
Experience maintaining legacy applications, including environments with incomplete documentation or evolving requirements.
Strong analytical, problem-solving, communication, and stakeholder collaboration skills.
Ability and willingness to work on-site five days per week in Decatur or East Peoria, Illinois.
Willingness to participate in a mandatory 24/7/365 on-call rotation approximately once every four weeks, including nights and weekends.
An associate degree or equivalent relevant experience may be considered; a bachelor's or master's degree is not mandatory.

Nice To Haves

Experience with Azure DevOps, GitHub, and source control workflows.
Knowledge of secure coding practices, application security, and vulnerability remediation.
Familiarity with GitHub Copilot or other approved AI-assisted development tools.
Exposure to C#, ASP.NET, or DB2.
Experience supporting manufacturing, industrial, or complex enterprise applications.
Ability to work effectively in a less-structured, waterfall-oriented development environment.

Responsibilities

Provide production support, maintenance, and operational stability for existing Java-based enterprise applications.
Investigate application incidents, identify root causes, and resolve issues involving application logic, databases, interfaces, performance, and deployments.
Develop, enhance, test, and maintain Java applications, services, integrations, and existing functionality.
Analyze business requirements and translate them into reliable, maintainable technical solutions.
Navigate legacy codebases to understand business logic and address issues arising from changing manufacturing processes.
Perform unit and integration testing, support system and user acceptance testing, and resolve identified defects.
Use Oracle databases and SQL to investigate data discrepancies and troubleshoot application-to-database interactions.
Collaborate with business users, technical teams, and stakeholders to assess reported issues and coordinate timely resolutions.
Identify application vulnerabilities and implement code changes to address security findings.
Use approved development tools and repositories, including Azure DevOps and GitHub.
Support technical reviews, deployment activities, production stabilization, and knowledge transfer.
Maintain accurate technical documentation and contribute to transition activities throughout the engagement.
Respond to production issues reported through ticketing systems, email, phone, Microsoft Teams, and direct user requests.
Coordinate with other teams when issues originate outside the application's scope.
Participate in a mandatory 24/7/365 on-call rotation approximately once every four weeks, running Monday through Monday and including nights and weekends.