IBM and BEA have released a new version of the Service Data Objects specification, version 2.0. You can get it from IBM or BEA.
SDO is not part of J2EE, but BEA and IBM are trying to make it a Java specification through JSR 235: Service Data Objects.
I cannot find an explanation of what the new features are in 2.0, or of what's changed between 1.0 and 2.0. Even the specification documents don't seem to explain what's changed. The IBM article simply says: "As of June 2005, an updated and extended version of the SDO Specification is available - Version 2.0. This has been enhanced in a number of areas, incorporating feedback received from the original version 1.0 specification." The BEA article doesn't even say that the spec's been updated; you just get the 2.0 version now.
The SDO spec is important to WAS developers because SDOs are the standard data access approach for WAS's implementation of JavaServer Faces (JSF), the mediations feature in the Service Integration Bus, data access capabilities, etc. The new spec version indicates how these features are likely to change in the future.
If you know what's new in SDO 2.0, please post a comment here or e-mail me. Thanks.