code: public NamespaceResourceInner createOrUpdate(String resourceGroupName, String namespaceName, NamespaceCreateOrUpdateParameters parameters) {
          return createOrUpdateWithServiceResponseAsync(resourceGroupName, namespaceName, parameters).toBlocking().single().body();
      }
docs: Creates/Updates a service namespace. Once created, this namespace's resource manifest is immutable. This operation is idempotent.
  
  @param resourceGroupName The name of the resource group.
  @param namespaceName The namespace name.
  @param parameters Parameters supplied to create a Namespace Resource.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @throws CloudException thrown if the request is rejected by server
  @throws RuntimeException all other wrapped checked exceptions if the request fails to be sent
  @return the NamespaceResourceInner object if successful.