code: public DataMigrationServiceInner beginCreateOrUpdate(String groupName, String serviceName, DataMigrationServiceInner parameters) {
          return beginCreateOrUpdateWithServiceResponseAsync(groupName, serviceName, parameters).toBlocking().single().body();
      }
docs: Create or update DMS Instance.
  The services resource is the top-level resource that represents the Data Migration Service. The PUT method creates a new service or updates an existing one. When a service is updated, existing child resources (i.e. tasks) are unaffected. Services currently support a single kind, "vm", which refers to a VM-based service, although other kinds may be added in the future. This method can change the kind, SKU, and network of the service, but if tasks are currently running (i.e. the service is busy), this will fail with 400 Bad Request ("ServiceIsBusy"). The provider will reply when successful with 200 OK or 201 Created. Long-running operations use the provisioningState property.
  
  @param groupName Name of the resource group
  @param serviceName Name of the service
  @param parameters Information about the service
  @throws IllegalArgumentException thrown if parameters fail the validation
  @throws ApiErrorException thrown if the request is rejected by server
  @throws RuntimeException all other wrapped checked exceptions if the request fails to be sent
  @return the DataMigrationServiceInner object if successful.