I'm looking for an expert Java Spring Boot & React developer who can address several critical issues with the existing codebase and further enhance its functionality. The key tasks and requirements include:

- **Codebase Troubleshooting**: The application is currently experiencing multiple issues including not running properly, showing error messages, and providing incorrect functionality.
- **Upload & Process CSV File**: The application should allow users to upload CSV files for processing. Upon CSV upload, the system should:
  - Parse and validate the data in the CSV file.
  - Store the validated data in a PostgreSQL database.
  - Provide a user-friendly error message in case the uploaded file is not in CSV format.

Ideal candidates for this project should have:
- Extensive experience with Java Spring Boot & React development.
- Proven track record of troubleshooting and fixing software applications.
- Proficiency in working with PostgreSQL database.
- Solid understanding of CSV parsing and data validation.
- Good communication skills and ability to work through tasks efficiently.

Please include relevant examples of your past work when applying for this project. Additional details will be shared with the selected candidate.