src/main/java/com/conveyal/gtfs/loader/JdbcGtfsExporter.java
private void cleanUpZipFile() {
        long startTime = System.currentTimeMillis();
        // Define ZIP File System Properties in HashMap
        Map<String, String> zip_properties = new HashMap<>();
        // We want to read an existing ZIP File, so we set this to False
        zip_properties.put("create", "false");

        // Specify the path to the ZIP File that you want to read as a File System
        // (File#toURI allows this to work across different operating systems, including Windows)
        URI zip_disk = URI.create("jar:" + new File(outFile).toURI());

        // Create ZIP file System
        try (FileSystem fileSystem = FileSystems.newFileSystem(zip_disk, zip_properties)) {
            // Get the Path inside ZIP File to delete the ZIP Entry
            for (String fileName : emptyTableList) {
                Path filePath = fileSystem.getPath(fileName);
                // Execute Delete
                Files.delete(filePath);
                LOG.info("Empty file {} successfully deleted", fileName);
            }
        } catch (IOException e) {
            LOG.error("Could not remove empty zip files");
            e.printStackTrace();
        }
        LOG.info("Deleted {} empty files in {} ms", emptyTableList.size(), System.currentTimeMillis() - startTime);
    }
private void cleanUpZipFile() {
        long startTime = System.currentTimeMillis();
        // Define ZIP File System Properties in HashMap
        Map<String, String> zip_properties = new HashMap<>();
        // We want to read an existing ZIP File, so we set this to False
        zip_properties.put("create", "false");

        // Specify the path to the ZIP File that you want to read as a File System
        // (File#toURI allows this to work across different operating systems, including Windows)
        URI zip_disk = URI.create("jar:" + new File(outFile).toURI());

        // Create ZIP file System
        try (FileSystem fileSystem = FileSystems.newFileSystem(zip_disk, zip_properties)) {
            // Get the Path inside ZIP File to delete the ZIP Entry
            for (String fileName : emptyTableList) {
                Path filePath = fileSystem.getPath(fileName);
                // Execute Delete
                Files.delete(filePath);
                LOG.info("Empty file {} successfully deleted", fileName);
            }
        } catch (IOException e) {
            LOG.error("Could not remove empty zip files");
            e.printStackTrace();
        }
        LOG.info("Deleted {} empty files in {} ms", emptyTableList.size(), System.currentTimeMillis() - startTime);
    }
Removes any empty zip files from the final zip file.