Subject:   JDO thoughts
Date:   2002-12-20 03:16:15
Response to: JDO thoughts

Hello again David,

Yes, I am a member of the JDO Expert Group. However my membership was only ratified about 6 months before JDO was submitted to JCP for final approval, at which stage the first Proposed Final Draft was already published. I had input on usability, from a non-Vendor's perspective, but the key architectural decisions had been bedded down by that stage. Someone who could give a better impression of any "undue influence" on these decisions would be David Jordan, author of the "Castor JDO - Simply False Advertising" article, as he was there from the beginning.

Versant and FastObjects were the vendors I had in mind as having pre-existing products in the space. I'm not sure what FrontierSuite for J2EE comprised. The rest are companies which may, I suppose, have had experience implementing aspects of the ODMG spec in some past life!

To be approved a JSR must provide the specification, the Toolset Compatibility Kit (TCK) tests, and a Reference Implementation (RI). The RI needs to be functionally correct so that it can be used by Vendors to identify the correct behaviour of an implementation.

It happens that Tomcat is a reference implementation that is so good it is also widely used as a servlet container in real web applications. Unfortunately Sun Microsystems was going through the pain of the current downturn in IT revenues at the time that the JDO RI was being implemented. As a result the amount of resource dedicated to that project was significantly reduced. Finally, the presence of so many commercial implementations in Beta at the time the RI was under development meant that there was no scope for the RI to become the de-facto standard, even if additional resource had been made available.

Hence we have an RI that is used by JDO Vendors to verify the functionality of their products, but which is generally not employed by JDO Users.

Happy Christmas!

Robin M. Roos