Complaint Management System

What I built I developed a full-stack Complaint Management System to securely handle user grievances. The application features a Spring Boot (Java 17) REST API backend using Spring Data JPA with MySQL, and a component-driven React.js frontend. To mirror enterprise standards, I established CI/CD pipelines using GitHub Actions and Jenkins, implemented a dynamic frontend CSV export feature using native JavaScript Blob objects to minimize backend load, and deployed the system to handle concurrent client requests efficiently.

What broke and what I figured out During integration, frontend requests were consistently blocked by CORS policy errors because my initial approach of using overly permissive @CrossOrigin("*") annotations was insecure and inadequate for production environments. Additionally, my CI/CD pipelines failed instantly due to a JDK version mismatch (runners defaulted to JDK 11, while the build required JDK 17). By centralizing the CORS policy into a dedicated WebMvcConfigurer bean and explicitly upgrading the CI runner configurations to JDK 17, I resolved both issues, heavily reinforcing the importance of centralized security and strict environment parity in deployments.

How to Run Locally

1. Database Setup (MySQL)

Create a new MySQL database (e.g., cms_db). Update src/main/resources/application.properties:

spring.datasource.url=jdbc:mysql://localhost:3306/your_database_name?allowPublicKeyRetrieval=true&useSSL=false
spring.datasource.username=your_mysql_username
spring.datasource.password=your_mysql_password

2. Backend Setup (Spring Boot)

Requires Java (JDK 17+) and Maven.

mvn spring-boot:run

The server will start at http://localhost:9000.

3. Frontend Setup (React JS)

Requires Node.js and npm.

cd ReactApp
npm install
npm start

The frontend will open at http://localhost:3000. Both servers must be running simultaneously.