I would like to suggest 2 imporvements to the Meta webservice:
1.) It would be nice if you could specify the context/graph for the Put webservice if you wanted to Put metadata in other contexts that default.
2.) It would be nice to abstract the put webservice layer from the service calls made to update the metadata. I realze the SesameService already does this to an extent. However, I think it would be a better abstraction to factor out the business logic of putting/getting/deleting metadata from the webservice. So create a new "Service" class that is independent of "HttpServletRequest" (etc) for dealing with the metadata, and just use the MetaWebService.java class for just handling webservice interaction. This is already being done for the import/export webservice/services.