This week's book giveaways are in the Cloud and AI/ML forums. We're giving away four copies each of Cloud Native Patterns and Natural Language Processing and have the authors on-line! See this thread and this one for details.
However, the current EJB CMP model is being replaced with the next version of the EJB and J2EE specs, with a lightweight 'plain old java objects' persistence model very similar to JDO (Java Data Objects). So JDO 2 will give you a much better solution today than CMP 2.x, and a much better migration path to EJB 3 in the future.
And there are more than 20 open source and commercial implementations of the JDO standard. The open source ones are free too if licensing costs is an issue.
Dave Clark<br />Senior WebSphere Architect<br /><a href="http://www.versant.com" target="_blank" rel="nofollow">Versant Open Access - JDO2 & EJB3</a>