I am attempting to resolve an issue with inserting empty blobs. We originally had our blobs mapped to byte[] but when storing a byte[0] hibernate considers this a null and then the insertion fails. We switched to using java.sql.Blob which resolved the problem until we added Apache Derby to the mix. Derby's blobs are only valid till the end of the transaction which isn't compatible with our existing code. I was reading about using a Hibernate User Type to act as some kind of middle man between blob and byte[] but I am not sure if this is appropriate. I also do not understand how to use a Hibernate user type.

Does anyone have a better way to deal with blobs that can be of zero length? Is a Hibernate User Type the proper solution? Should I really be only handling blobs in transactions and refactor the entire codebase (Please say no)?

Regards,
Thomas

I ended up copying a merge of PrimitiveByteArrayBlobType and ByteArrayBlobType that does not use streams. Then annotate the blob member with



I tried just modifying the dialect to return false to Dialect.useInputStreamToInsertBlob() but WrappedMaterializedBlobType does not seem to obey this. I am not sure if it uses some other method that is neither stream not setBlob but it doesn't work.

Regards,
Thomas