Thank you for your very interesting article that demonstrates the power of JDBC 2.0. It is a pitty that so few developers actually even know that this can be done in JDBC, so blinded by all the hype around entity EJBs and now JDO.
My concern about the approach you demonstrate, however, is its actual "portability". JDBC 2.0 is around for quite a long time now and it is still difficult to find JDBC drivers (even costly ones) that can exploit JDBC 2.0-specific features like access to the object layer of ORDBMS, scrollable and updateable result sets, etc. Visibly, Oracle is quite capable. But what is the "state of the market" with regard to that type of solution? I would welcome a list of JDBC drivers/database combinations that are known to work with this solution (I say "known to work" because from experience there is often some gap between the supposed and actual capability of a JDBC driver due to poor implementation), and preferrably at a reasonable cost as far as many small companies can't afford big guns like Oracle. An advantage of JDO is that most implementations will probably only rely on JDBC 1.0 features and work even with free databases like MySQL and others.