Java Database Connectivity (JDBC) is an application programming interface (API) for the programing language Java, which defines how a client may access any quite tabular data, especially relational databases. it's a part of the Java Standard Edition platform, from Oracle Corporation. It acts as a middle layer interface between java applications and databases.

The JDBC classes are contained within the Java Package java.sql and javax.sql.
JDBC helps you to write down Java applications that manage these three programming activities:

1. Connect to a knowledge source, sort of a database.
2. Send queries and update statements to the database
3. Retrieve and process the results received from the database in answer to your query

The JDBC driver is a client adapter (installed on the client machine, not on the server) that converts requests

Java Database Connectivity (JDBC) is an API that provides a set of classes and interfaces for accessing a database from a Java application. A JDBC driver is a software component that enables a Java application to interact with a database.

There are four types of JDBC drivers:

1. Type 1: JDBC-ODBC Bridge Driver This driver translates JDBC calls into ODBC calls, which are then sent to the database. It requires the presence of ODBC driver to connect to the database.

2. Type 2: Native API Partly Java Driver This driver uses the database vendor's native API to connect to the database. It requires the database vendor's API to be installed on the client machine.

3. Type 3: Network Protocol Driver This driver uses a middleware component to convert JDBC calls to the vendor-specific database protocol. It requires the middleware component to be installed on the client machine.

4. Type 4: Thin Driver This driver is a pure Java implementation that communicates directly with the database server using the database's native protocol. It does not require any vendor-specific library or middleware component to be installed on the client machine.

Each type of driver has its advantages and disadvantages in terms of performance, portability, and installation requirements. Type 4 drivers are the most commonly used drivers as they are platform-independent and do not require any additional installation.