Java Spring Backend & API Development

I need a seasoned Java developer with extensive experience in SQL and Spring for a backend project. The task involves developing an API in Java.

Key points:
- The primary purpose of the API hasn't been defined yet, so flexibility and a strong understanding of different API functionalities will be essential.
- The type of database to be used has not been selected, your expertise in MySQL, PostgreSQL, and Oracle will be highly valuable.
- The backend will need to support various functionalities, including but not limited to Authentication, Data storage, and potentially Real-time updates.

Ideal skills for the job include:
- Proficiency in Java, SQL, and Spring.
- API development experience.
- Database management skills.
- Flexibility and adaptability to changing project requirements.