Using the BEA Aqualogic Data Services Platform, Workshop version 8.1.4, I had trouble building the SDO mediator client JAR. The problem was that none of my changes were making it into the client JAR. I discovered that you must manually rebuild the application EAR file first -- rebuilding the application alone is not enough. Apparently, Workshop never rebuilds the EAR file automatically -- at least I haven't found a way to do so. The 'clean application' command does not delete the EAR file. Note it doesn't matter whether or not the WebLogic server is running during any of these activities.
As an aside, I cannot find any way at all to delete an imported relational data service. I had imported a table called 'well'. I manually deleted the DS file, and rebuilt the application. It was unable to compile another data service that referenced 'well' as a relationship. I manually deleted the relationship function, and then the application built completely. However... when I created the client JAR, 'well' was still there. I can't find any reference to it anywhere, so I'm not sure why it is still turning up.