Understanding Data Source
The JDBC API provides the DataSource interface as an alternative to the DriverManager for establishing the connection.
A DataSource object is the representation of database or the data source in the Java programming language. DataSouce object is mostly preferred over the DriverManager for establishing a connection to the database.
DataSource object can be thought as a factory for making connections to the particular database that the DataSource instance represents.
DataSource has a set of properties that identify and describe the real world data source that it represents. The properties include information about the location of the database server, the network protocol use to communicate with the server the name of the database and so on.
DataSource object works with JNDI (Java Naming and Directory interface) naming service so application can use the JNDI API to access the DataSource object.
In short we can say that the DataSource interface is implemented to provide three kinds of connections:
1). Basic DataSource class
This class is provided by the driver vendor. It is used for portability and easy maintence.
2). To provide connection pooling.
It is provided by the application server vendor or driver vendor. It works with ConnectionPoolDataSource class provided by a driver vendor. Its advantage is portability, easy maintenence and increased performance.
3). To provide distributed transactions
This class works with an XADataSource class, which is provided by the driver vendor. Its advantages are easy maintenence, portability and ability to participate in distributed transactions.