A temporary (until fixed) work-around is to execute:
SELECT lo_create(0)
And do a
ResultSet.getBlob(1)
I have not tried it, but this may also work with EntityManager:
.createNativeQuery("SELECT lo_create(0)", Blob.class).getSingleResult();
In PostgreSQL Blobs are not exactly the same thing as the JDBC Blobs, in JDBC it seems Blobs are functional values, while in PostgreSQL they're more like stand-alone objects that can and must be managed on their own.
