Senior Java + AS400 Engineer | Remote | 15+ Years | Long Term

Role: Senior Java Engineer – AS400 & Application DevelopmentDuration: LongtermLocation: NJ-based, (Remote)Experience: 15+ years total Engagement: Multi-application support and project deliveryVisa: Any Visa is fineRole Summary:We are looking for a senior Java engineer with deep L3 and L4 support experience and extensive hands-on work on the IBM i (AS400) platform. The role combines production support, complex solution development, and architectural input across multiple business applications. You will resolve escalated incidents, drive root cause analysis, enhance existing systems, and contribute to project delivery in a structured ITIL-governed environment.Key Responsibilities:Provide L3 and L4 support for business-critical applications: troubleshoot escalated incidents, perform root cause analysis, and implement permanent fixes.Design, develop, and deploy complex Java-based solutions and integrations, including those that interface with IBM i / AS400 systems.Contribute to solution design and architecture: review technical designs, recommend patterns, and guide modernization and integration decisions.Support and enhance multiple applications concurrently, prioritizing effectively across incidents, problems, changes, and project work.Participate actively in projects from requirements and design through build, testing, deployment, and hypercare.Manage incidents, problems, changes, and service requests in ServiceNow in line with ITIL processes and SLAs.Plan and track work in JIRA (stories, tasks, defects, sprints, boards, dashboards).Perform code reviews, enforce coding standards, and mentor junior and mid-level engineers.Create and maintain technical documentation, runbooks, knowledge articles, and support handover material.Collaborate with business users, QA, DevOps, infrastructure, and vendor teams; communicate status and risks clearly to stakeholders.Participate in on-call or shift rotations and major incident bridges as required.Required Qualifications:15+ years of total IT experience, with strong Java development and support experience.Proven L3 and L4 support background: complex defect analysis, code-level fixes, performance tuning, and vendor escalation handling.Extensive hands-on experience on the AS400 / IBM i platform.Experience writing complex solutions and some level of architecture experience (solution design, integration design, technical leadership).Demonstrated ability to support multiple applications at the same time and engage in project work.Full understanding of ITIL: incident, problem, change, release, and knowledge management, SLAs, and major incident handling (ITIL v3/v4 certification preferred).Hands-on experience with ServiceNow (SNOW) for ITSM and JIRA for work management.Excellent analytical, communication, and stakeholder management skills.Technical SkillsCore Java and frameworksJava 8 / 11 / 17+, OOP, multithreading and concurrency, collections, streams, JVM tuning and memory managementSpring Framework, Spring Boot, Spring MVC, Spring Data, Spring Security, Spring Batch, Spring CloudHibernate / JPA, MyBatis, JDBCJakarta EE (Servlets, JSP, EJB, JMS), legacy Struts exposure a plusWeb services and integrationREST and SOAP web services, JSON / XML, Swagger / OpenAPIMessaging: JMS, Apache Kafka, ActiveMQ, RabbitMQ, IBM MQIntegration patterns, ESB / middleware exposure (Oracle SOA/OSB, MuleSoft, or similar)Microservices architecture, API gateway concepts, OAuth2 / JWTIBM i / AS400IBM i (AS400) architecture, DB2 for i, libraries, objects, and job managementRPG / RPGLE, CL, COBOL awareness; reading and troubleshooting legacy codeJT400 / JTOpen toolkit, JDBC to DB2 for i, data queues, program calls, and Java-to-RPG integrationBatch job scheduling, spool file handling, and performance analysis on IBM iModernization approaches: API enablement, service wrapping, and incremental refactoringDatabasesDB2, Oracle, SQL Server, or PostgreSQL; advanced SQL, stored procedures, query tuning and indexingBuild, DevOps, and qualityMaven / Gradle, Git, Bitbucket / GitHub / GitLab, Jenkins or equivalent CI/CDJUnit, Mockito, integration testing, SonarQube / code quality toolsDocker; Kubernetes and cloud (AWS / Azure / OCI) exposure a plusApplication servers and web servers: WebLogic, WebSphere, Tomcat, JBoss, Apache / NginxMonitoring and troubleshootingLog analysis, thread and heap dump analysis, profiling and performance tuningMonitoring and APM tools such as Splunk, ELK, Dynatrace, AppDynamics, or New RelicService management and delivery toolsServiceNow (incident, problem, change, knowledge, reporting), JIRA, ConfluenceITIL-aligned processes, SLA and KPI reporting, RCA and problem record documentationPreferred QualificationsITIL Foundation or higher certification; Oracle or Java certificationsExperience in retail, publishing, distribution, or ERP-integrated environmentsExposure to Agile / Scrum and hybrid support-plus-project delivery modelsExperience modernizing or migrating legacy platformsExperience working with onshore/offshore delivery teamsSoft SkillsStrong ownership and accountability for production stabilityCalm and structured under major incident pressureClear written and verbal communication with technical and business audiencesAbility to mentor and influence without formal authoritySelf-driven, able to context-switch across applications and priorities