It is nice and imho a good addition.
However, notice that you did not need to create a specialized MyOwnDataArrayHandlers (except if you want to make advanced stuff). Just setting the FETPAPI DataArrayHandlers would have been sufficient :
session.setDataArrayProtocolHandlers(new DataArrayHandlers(session));
If you don’t set this handler, your client is not informed that it is going to deal with the DataArray Protocol which may lead to a bug if you actually use it.
I even don’t understand exactly why I don’t see a bug on my environment even when I don’t set this handler and call GetXYZ. I’ll look at it.