Java Backend Developer for Web App

I'm in need of a skilled Java backend developer to support the development of a web application. The backend should ideally be compatible with PostgreSQL, which is my preferred database technology.

Key Skills and Experience:
- Extensive experience in Java, specifically for web applications
- Proficient in PostgreSQL
- Prior work with backend development for web apps is preferred
- Knowledge in implementing user authentication, data storage and retrieval, and payment processing would be a plus.