JDBC (Java Database Connectivity) is a technology which is used to communicate a java application with database application.

JDBC is a simple java program(.java file) which is used to connect with database. Communicating with database means to connect to database, retrieve data from database, and perform various operations in the database.

So JDBC is a java based data access technology to interact with database.

Here in this context Java application is communicating with database with the help of JDBC Driver. That means JDBC driver act as mediator.
JDBC Driver is nothing but software that has developed according to JDBC API.

JDBC API is a document containing some inbuilt classes and interfaces. JDBC API is a part of the java platform Standard Edition (java SE) and is available to java platform Enterprise Edition (java EE). JDBC API is mainly divided into two packages, such as java.sql and javax.sql.