A JDBC developer designs, implements, and maintains Java applications that interact with databases. They use Java Database Connectivity (JDBC), an API for Java, to connect Java programs with various types of databases like MySQL, Oracle, and SQL Server. Their responsibilities include writing SQL queries, stored procedures, creating connections, and manipulating data. They also handle exceptions, manage transactions, and ensure data integrity. Furthermore, they optimize database performance, resolve issues, and adhere to security protocols. They collaborate with other developers and stakeholders, ensuring the application meets user needs and business requirements.