code: public void setServiceURL(String serviceURL) {
      if (Utility.isNullOrEmpty(serviceURL)) {
        this.serviceURL = DEFAULT_SERVICE_URL;
      } else {
        this.serviceURL = serviceURL;
      }
    }
docs: Sets the service URL. The service URL is typically of the form -
  <code>http[s]://host[:port]</code>. A <code>null</code> or empty string would result in
  connecting to the default Datastore on GCP. All other values, except
  {@link ConnectionParameters#DEFAULT_SERVICE_URL}, would be interpreted as a connection to the
  Datastore Emulator.
  
  @param serviceURL
  the serviceURL to set.