JDBC is just an API. Many of the JDBC drivers listed on Javasoft's Web site, and that are supposed to implement JDBC 2.0 capability indeed implement the API but:
a) throw an Exception when you invoke JDBC 2.0-specific methods. A typical example is the previous() method of ResultSet. Another could be the updateRow() method.
b) don't implement what the JDBC 2.0-specific technique is actually supposed to bring. A typical example is the batch update feature: the updates are often just sent one after the other.
I would be glad to hear about a successful experience with a solution other than Oracle. If I take the example of PostgreSQL, a JDBC 2.0 driver is indeed available, but doesn't implement SQLInput and SQLOutput. Hence...