Daniel,
Is it a Java SE application that uses Persistence.createEMF() to get a hold of the EM/EMF? Or is it a Java EE ap that uses injection/lookup for that purpose? If it's the latter, and you use GlassFish (can't say what other containers do), the GlassFish runtime (according to the spec requirements) sets the default Derby database (see jdbc/__default jdbc resource) as the datasource when it creates the objecy that represents your PU before createing an EMF in the background. Which means that your jdbc properties are ignored by the toplink code in that case.
Regards,
-marina
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