Returns a connection to a database as configured earlier.
This method can be used by all the jsps to get a connection.
The jsps do not have to worry about which db to connect to etc.
This has been configured in this class by the InitServlet.
Opens the connection to the MySQL Database
Using the DataSource Name specified in the config file of the server in
which it is deployed.
In real world applications,some sort of connection pooling mechanism
would be used for getting the connection and proper care would be taken
to
close it when the work is done.