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Turning the focus away from the more established JDBC and EJB technologies, Enterprise Java expert Kyle Gabhart puts the bright lights on JDO.

Application components fulfill requests for business services. To fulfill these requests, they often must change the state of the underlying datastore. It is imperative that those changes do not compromise the integrity of the persistent datastore. (In the first article on data persistence, we defined a persistent datastore as an independent data repository capable of preserving its data even in the event of a server crash or network failure.) To ensure persistence, application components must be capable of handling concurrency, connection management, data integrity, and synchronization. All three of J2EE's data management technologies handle these functions for the developer, although each one has its own way of doing so.

Last month we explored the pros and cons of entity beans versus JDBC. This month we'll see how Java Data Objects can be combined with stateless session beans and how that solution compares with the standard entity bean application. Since JDO is still a rather new technology (the youngest of J2EE's persistence solutions), we'll start with an overview of how it works.

for read more information:
http://www-128.ibm.com/developerworks/java/library/j-pj2ee4.html?open&ca=dgr-jw10j-pj2ee4