This quote is from jdbc tutorial that I have found on Oracle website.
In previous versions of JDBC, to obtain a connection, you first had to initialize your JDBC driver by calling the method Class.forName. This methods required an object of type java.sql.Driver. Each JDBC driver contains one or more classes that implements the interface java.sql.Driver. The drivers for Java DB are org.apache.derby.jdbc.EmbeddedDriver and org.apache.derby.jdbc.ClientDriver, and the one for MySQL Connector/J is com.mysql.jdbc.Driver. See the documentation of your DBMS driver to obtain the name of the class that implements the interface java.sql.Driver.
Any JDBC 4.0 drivers that are found in your class path are automatically loaded. (However, you must manually load any drivers prior to JDBC 4.0 with the method Class.forName.)