what is the difference between JDO (JSR 243) and SDO (JSR 235) in Java; what set of open source providers are available for these java specifications
From this article:
[...] JDO looks at the persistence issue only [...] whereas SDO is more general and represents data that can flow between any J2EE tier, such as between a presentation and business tier.
EclipseLink is one SDO provider, Apache's DB project is one JDO implementation.