Hello "s babu",
Welcome to JavaRanch. I think you need to first adjust your display name to match with JavaRanch's policies. It should be your firstname and the lastname.
DriverManager and DataSource serve different purposes. DriverManager is used to register a driver (
JDBC) for obtaining a connection from the specific database.
DataSource is used for managing the connections in an efficient manner as a connection is a costly resource.
Hope this helps you.