code: public Set<Class<? extends Exception>> getRetryableExceptions() {
      return retryableExceptions != null ? retryableExceptions : parent != null ? parent.getRetryableExceptions()
        : Collections.<Class<? extends Exception>>emptySet();
    }
docs: Returns the exceptions for which invocations will be retried. By default these will include
  {@code SocketTimeoutException}, {@code ConnectException}, {@code AlreadyClosedException}, and
  {@code TimeoutException}, but this set can be mutated directly to change the retryable
  exceptions.