Are you simply mapping a byte[] to the blob field in the DB, or are you mapping something else?
It seems from the traces that Toplink is trying to create some kind of object from the blob data (something besides a byte[] that is).
Have you tried making a simple test case where this fails?
I've had a good experience using blobs as byte[], but I'm using Postgres. So I dunno if this is a GF/Toplink or JDBC issue.
[Message sent by forum member 'whartung' (whartung)]
http://forums.java.net/jive/thread.jspa?messageID=249110