JDBC is part of the Java SE specification. In this simple demo video by Rudy De Busscher, learn how to define the data source within the JDBC framework in under 8 minutes.
JDBC is considered low-level as you need to retrieve and manage connections, statements, and results-sets yourself. If you fail to close or properly manage them, you'll have errors and exceptions. JDBC requires a lot of boilerplate code but the advantage of JDBC is the control you have over your database queries.