Mike Keith believe the JDO is out of date.
Then what role of JDO in ObjectDB?
Will our codes with JDO be out of date?
Due in part to some of the failures of the EJB persistence model, and some frustration at not having a satisfactory standardized persistence API, another persistence specification was attempted. Java Data Objects (JDO) was inspired and supported primarily by the object-oriented database (OODB) vendors and never really got adopted by the mainstream programming community. It required vendors to enhance the bytecode of domain objects to produce class files that were binary-compatible across all vendors, and every compliant vendor’s products had to be capable of producing and consuming them. JDO also had a query language that was decidedly object-oriented in nature, which did not sit well with relational database users, who were in an overwhelming majority. JDO reached the status of being an extension of the JDK, but never became an integrated part of the enterprise Java platform. It had many good features and was adopted by a small community of devoted users who stuck by it and tried desperately to promote it. Unfortunately, the major commercial vendors did not share the same view of how a persistence framework should be implemented. Few supported the specification, so JDO was talked about, but rarely used. Some might argue that it was ahead of its time and that its reliance on bytecode enhancement caused it to be unfairly stigmatized. This was probably true, and if it had been introduced three years later, it might have been better accepted by a developer community that now thinks nothing of using frameworks that make extensive use of bytecode enhancement. Once the EJB 3.0 persistence movement was in motion, however, and the major vendors all signed up to be a part of the new enterprise persistence standard, the writing was on the wall for JDO. People soon complained to Sun that they now had two persistence specifications: one that was part of its enterprise platform and also worked in Java SE, and one that was being standardized only for Java SE. Shortly thereafter, Sun announced that JDO would be reduced to specification maintenance mode and that JPA would draw from both JDO and the persistence vendors and become the single supported standard going forward.
There's never been infinity. Cantor's diagonal proof is completely wrong.