App.java

try {
  final String httpMethod = input.getHttpMethod();
  if ("GET".equalsIgnoreCase(httpMethod)) {
    final List<Pet> pets = DependencyModule.PET_STORE_CLIENT.read();
    final String result = DependencyModule.OBJECT_MAPPER.writeValueAsString(pets);
    return response.withStatusCode(200).withBody(result);
  } else {
    final Pet pet = DependencyModule.OBJECT_MAPPER.readValue(input.getBody(), Pet.class);
    final String id = DependencyModule.PET_STORE_CLIENT.write(pet);
    return response.withStatusCode(200).withBody(id);
  }
} catch (final IOException e) {
  return response.withStatusCode(500).withBody("{}");
}