Question

I’ve seen this type of code quite a bit in code which initializes the MySQL JDBC connection.

Class.forName("com.mysql.jdbc.Driver");
conn = DriverManager.getConnection("jdbc:mysql://10.0.0.2:3306", "username", "password");

Now my question is why/when is this first line required? I’ve been able to connect without any problems to a MySQL database by just having this:

conn = DriverManager.getConnection("jdbc:mysql://10.0.0.2:3306", "username", "password");

I’m using Java 7 with the Connector/J 5.0.8 driver.

I don’t have any import or class loading statements in my code which would directly load the MySQL driver, only the generic Java SQL interface classes.

Answer 1

Short answer : With JDBC drivers prior 4.0 (JDBC 4.0 introduce auto-loading of JDBC driver class)

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.)

Source: JDBC Basics