StdJDBCDelegate fails to free its blobs in getObjectFromBlob and getJobDataFromBlob.
The ResultSet API explicitely says that closing the ResultSet won't free the Blob :
"The closing of a ResultSet object does not close the Blob, Clob or NClob objects created by the ResultSet. Blob, Clob or NClob objects remain valid for at least the duration of the transaction in which they are creataed, unless their free method is invoked."
Most JDBC implementations will free the resources at the end of the transaction, but notice the API says "at least the duration of the transaction", not at most...
Using for example CachéDB, not freeing the blobs results in stuck resources.
Proposed patch encloses calls to rs.getBlob in try / catch and call blob.free() in finally, to explicitely release the resources of the blobs.