JDBC DataSource In JDBC another way of Connecting to Database using DataSource Object. It provides Connection Pooling and Distributed Transaction support.
Connection Pooling is a mechanisam where pool of connections are already created and ready for use. When programmer requestes for connection, DataSource object simply returns Connection Object from ConnectionPool. When there are no connections,all connections are idle in state.
Distributed Transactions : Application using multiple databases with in the same Transaction, Databases can be on the local system or in the network,or in web.