Export big json file

ExportJsonFile.java

private ObjectMapper jsonMapper = new ObjectMapper();
private ExecutorService executorService = Executors.newFixedThreadPool(5);
 
@Async
public ListenableFuture<Boolean> export(UUID customerId) {
    try (PipedInputStream in = new PipedInputStream();
            PipedOutputStream pipedOut = new PipedOutputStream(in);
            GZIPOutputStream out = new GZIPOutputStream(pipedOut)) {
     
        Stopwatch stopwatch = Stopwatch.createStarted();
 
        ObjectWriter writer = jsonMapper.writer().withDefaultPrettyPrinter();
 
        try(SequenceWriter sequenceWriter = writer.writeValues(out)) {
            sequenceWriter.init(true);
         
            Future<?> storageFuture = executorService.submit(() ->
                   storageProvider.storeFile(getFilePath(customerId), in));
 
            int batchCounter = 0;
            while (true) {
                List<Record> batch = readDatabaseBatch(batchCounter++);
                for (Record record : batch) {
                    sequenceWriter.write(entry);
                }
                if (batch.isEmpty()) {
                    // if there are no more batches, stop.
                    break;
                }
            }
 
            // wait for storing to complete
            storageFuture.get();
 
            // send the customer a notification and a download link
            notifyCustomer(customerId);
        }  
 
        logger.info("Exporting took {} seconds", stopwatch.stop().elapsed(TimeUnit.SECONDS));
 
        return AsyncResult.forValue(true);
    } catch (Exception ex) {
        logger.error("Failed to export data", ex);
        return AsyncResult.forValue(false);
    }
}