/**
 * Create a class.
 *
 * @param issuerId The issuer ID being used for this request.
 * @param classSuffix Developer-defined unique ID for this pass class.
 * @return The pass class ID: "{issuerId}.{classSuffix}"
 */
public String createClass(String issuerId, String classSuffix) throws IOException {
  // Check if the class exists
  try {
    service.genericclass().get(String.format("%s.%s", issuerId, classSuffix)).execute();

    System.out.printf("Class %s.%s already exists!%n", issuerId, classSuffix);
    return String.format("%s.%s", issuerId, classSuffix);
  } catch (GoogleJsonResponseException ex) {
    if (ex.getStatusCode() != 404) {
      // Something else went wrong...
      ex.printStackTrace();
      return String.format("%s.%s", issuerId, classSuffix);
    }
  }

  // See link below for more information on required properties
  // https://developers.google.com/wallet/generic/rest/v1/genericclass
  GenericClass newClass = new GenericClass().setId(String.format("%s.%s", issuerId, classSuffix));

  GenericClass response = service.genericclass().insert(newClass).execute();

  System.out.println("Class insert response");
  System.out.println(response.toPrettyString());

  return response.getId();
}