RPC Methods with no args fail to return the result

In RestConfImpl, when RPC methods that have no input arguments are implemented, they fail to return the result. The implementation returns a valid result object, but somewhere down the line, most likely in RestConfImpl's invokeRPC method, the result object becomes null. The user, as a result, gets a HTTP 204 No Content for their query. There are no exceptions printed out.

If I change the RPC to accept a dummy input argument, everything else remaining same, things work fine.