Mohan Raj Gurusamy

Designed and maintained enterprise applications using Java 17, Spring Boot/Spring MVC, Spring Data JPA, and React with Material UI. Developed scalable RESTful APIs and microservices with business validation, exception handling, structured logging, and integrations with downstream systems. Built reusable React/MUI components and connected frontend with backend APIs for responsive, maintainable user experiences. Implemented security using Spring Security with OAuth2 and JWT and collaborated on architecture discussions covering scalability, performance, security, databases, infrastructure, and middleware. Partnered with DevOps teams on Docker, Kubernetes, and PCF deployments with CI/CD automation via Jenkins/GitHub Actions/Spinnaker. Owned features across the full lifecycle including testing, deployment, production support, troubleshooting, and root-cause analysis.

Led design and development of cloud-native microservices using Spring Boot, Java 17, and React. Modernized Java 8 services to Java 17 to improve runtime efficiency, maintainability, and security posture. Implemented authentication and role-based access control with Spring Security using JWT and OAuth2. Built messaging-driven capabilities using Apache Kafka (and Zookeeper) and JMS, including smooth processing using Spring Kafka. Developed caching strategies with Redis to reduce database load and latency. Enhanced UI with Material UI, created observability dashboards and alerts in Looker and Grafana, and optimized database queries/indexes in PostgreSQL and MongoDB. Automated CI/CD workflows in Jenkins and documented APIs with Swagger/OpenAPI; mentored junior developers and collaborated with architects to define API contracts.

Developed Spring Boot microservices and REST APIs integrating PostgreSQL, Oracle, and MongoDB, including data access layers via Spring Data JPA. Implemented Spring Security for authentication/authorization using OAuth2 and JWT token management. Wrote complex SQL, optimized stored procedures, and supported high-throughput processing. Deployed microservices to Pivotal Cloud Foundry (PCF) using manifest configurations and blue-green strategies for zero-downtime releases. Integrated external REST and SOAP services with payload transformation and robust error handling. Built Jenkins CI/CD pipelines for automated builds, analysis, and deployments; implemented unit/integration testing with JUnit and Mockito. Applied event-driven patterns using Kafka to decouple systems, documented APIs with Swagger/OpenAPI, and supported production incidents with centralized logging/monitoring.