The JDBC Connection Classes

The JDBC Classes for Creating a Connection
==========================================
JDBC uses on class (java.sql.DriverManager) and two interfaces
(java.sql.Driver and java.sql.Connection) for connecting to a database. The
following note provides a brief introduction to these three java
interface/classes:
java.sql.Driver
---------------
Unless you are writing your own custom JDBC implementation, you should
never have to deal with this class from you application. It simply gives
JDBC a launching point for database connectivity by responding to
DriverManager connection requests and providing information about the
implementation in question.
java.sql.DriverManager
----------------------
Unlike most other parts of JDBC, DriverManager is a class instead of an
interface. Its main responsibility is to maintain a list of Driver
implementations and present an application with one that matches a
requested URL. The DriverManager provides registerDriver() and
deregisterDriver() methods, which allow a Driver implementation to
register itself with the DriverManager or remove itself from the list. You
can get an enumeration of registered drivers through the getDrivers()
method.
java.sql.Connection
-------------------
The Connection class represents a single logical database connection. In
other words, you use the Connection class for sending a series of SQL
statements to the database and managing the commiting or aborting (rollback)
of those statements.