Java Database Connectivity (JDBC) is an API that enables Java developers to access any tabular data source (e.g relational databases) from Java code. The API comes as a set of classes in the java.sql package that enable Java applications to talk to databases.
Most databases speak a language called SQL (Structured Query Language). SQL allows you to ask the database for some set of data and receive the results. SQL is a standard language, in its simple forms, although many database vendors have implemented extensions to standard SQL. JDBC gives you the opportunity to speak standard SQL to any database, using a special piece of software called a JDBC driver. To use JDBC with a particular brand of database, you need a JDBC driver for that database. In addition to access to relational databases, the latest release of JDBC technology (JDBC 2.0 API) provides access to non-database tabular sources of data such as spreadsheets and flat files.
For more information on JDBC technology, visit java.sun.com/products/jdbc/.