The JDBC Optional Package (formerly known as the Standard Extension API) adds functionality that mostly applies if you are building distributed applications in which multiple clients are accessing remote databases. However, there is some functionality that applies generally to all JDBC development.
As mentioned before, the core JDBC API resides in the java.sql package. The optional package resides in the javax.sql package alone. The optional package includes four new high-level features:
A RowSet object is designed to be a container for a collection or set of rows. The RowSet is not provided by the driver implementation, but rather is implemented ...