public static class DefaultToMinTimestampPlusOneHour implements DefaultValueFactory<Long> {
  @Override
  public Long create(PipelineOptions options) {
    return options.as(Options.class).getMinTimestampMillis()
      + Duration.standardHours(1).getMillis();
  }
}

...

static void runWindowedWordCount(Options options) throws IOException {
  final String output = options.getOutput();
  final Instant minTimestamp = new Instant(options.getMinTimestampMillis());
  final Instant maxTimestamp = new Instant(options.getMaxTimestampMillis());

  Pipeline pipeline = Pipeline.create(options);
  Pipeline p = Pipeline.create(options);

    pipeline
        .apply(ParDo.of(new AddTimestampFn(minTimestamp, maxTimestamp)))
        .apply(Window.<String>into(FixedWindows.of(Duration.standardMinutes(1)))
                                      .triggering(AfterWatermark.pastEndOfWindow()
                                      .withEarlyFirings(
                                          AfterProcessingTime.pastFirstElementInPane()
                                              .plusDelayOf(Duration.standardMinutes(1)))
                                      .withLateFirings(
                                          AfterProcessingTime.pastFirstElementInPane()
                                              .plusDelayOf(Duration.standardMinutes(2))))
                              .withAllowedLateness(Duration.standardMinutes(1))
                              .accumulatingFiredPanes())
        .apply(new WordCount.CountWords())
        .apply(MapElements.via(new WordCount.FormatAsTextFn()))
        .apply(new WriteOneFilePerWindow(output, options.getNumShards()));

public static void main(String[] args) throws IOException {
Options options = PipelineOptionsFactory.fromArgs(args).withValidation().as(Options.class);

  runWindowedWordCount(options);
 }
}