如果内部PDF大小很大，则在创建投资组合时出现问题

Question

在创建投资组合pdf时，如果任何pdf大小很大或者如果页面中包含大量没有，那么组合pdf就不会被创建。它也不会抛出任何错误。请找到以下代码：

 public byte[] createPortFolio(String directoryName) throws DocumentException, IOException {

    Document document = new Document();

    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    PdfWriter writer = PdfWriter.getInstance(document, baos);
    document.open();
    document.add(new Paragraph("This document contains a collection of PDFs, one per Stanley Kubrick movie."));

    PdfIndirectReference parentFolderObjectReference = writer.getPdfIndirectReference();
    PdfDictionary parentFolderObject = GetFolderDictionary(folderCount);
    parentFolderObject.put(PdfName.NAME, new PdfString("Root"));

    PdfCollection collection = new PdfCollection(PdfCollection.CUSTOM);
    PdfCollectionSchema schema = getCollectionSchema();
    collection.setSchema(schema);

    PdfCollectionSort sort = new PdfCollectionSort("File");
    sort.setSortOrder(true);
    collection.setSort(sort);
    collection.put(new PdfName("Folders"), parentFolderObjectReference);
    writer.setCollection(collection);
    listFilesAndFilesSubDirectories(writer, collection, schema, directoryName, parentFolderObject, parentFolderObjectReference);

    document.close();

    return baos.toByteArray();
}

 public void listFilesAndFilesSubDirectories(PdfWriter writer, PdfCollection collection, PdfCollectionSchema schema, String directoryName, PdfDictionary parentFolderObject, PdfIndirectReference parentIndirectReference) throws DocumentException, IOException {

    File directory = new File(directoryName);
    //get all the files from a directory
    File[] fList = directory.listFiles();
    String sStatus = "";

    PdfIndirectReference siblingFolderObjectReference = null;
    PdfDictionary siblingFolderObject = null;

    PdfIndirectReference childFolderObjectReference = null;
    PdfDictionary childFolderObject = null;

    for (File file : fList) {
        if (file.isFile()) {
            createPdf(writer, schema, file, parentFolderObject);//adding PDF in Portfolio
        } else if (file.isDirectory()) {
            childFolderObjectReference = writer.getPdfIndirectReference();
            folderCount++;
            if (siblingFolderObject != null && parentIndirectReference.equals(siblingFolderObject.get(PdfName.PARENT))) {
                siblingFolderObject.put(PdfName.NEXT, childFolderObjectReference);
                writer.addToBody(siblingFolderObject, siblingFolderObjectReference);
            } else {
                parentFolderObject.put(new PdfName("Child"), childFolderObjectReference);
            }

            childFolderObject = GetFolderDictionary(folderCount);
            childFolderObject.put(PdfName.NAME, new PdfString(file.getName()));
            childFolderObject.put(PdfName.PARENT, parentIndirectReference);
            siblingFolderObjectReference = childFolderObjectReference;
            siblingFolderObject = childFolderObject;

            writer.addToBody(parentFolderObject, parentIndirectReference);
            writer.addToBody(childFolderObject, childFolderObjectReference);

            listFilesAndFilesSubDirectories(writer, collection, schema, file.getAbsolutePath(), childFolderObject, childFolderObjectReference);
        }
    }
}
private void createPdf(PdfWriter writer, PdfCollectionSchema schema, File fileObj, PdfDictionary parentFolderObject) {

    PdfFileSpecification fs=null;
    PdfCollectionItem item;

    //Adding first File
    try{
        fs = PdfFileSpecification.fileEmbedded(writer, fileObj.getPath(), fileObj.getName(), null, true, null, null);
        //fs=fileEmbedded(writer, fileObj.getPath(), fileObj.getName(), null, true, null, null);

    }
    catch(Exception ex)
    {
        System.out.println("in Exception   "+ex.getMessage());
        ex.printStackTrace();
    }
    finally
    {
        System.out.println("in finally block");
    }

    item = new PdfCollectionItem(schema);
    item.addItem("Type", "pdf");
    fs.addCollectionItem(item);

    try{
        writer.addFileAttachment(fs);   
    }
    catch(Exception ex)
    {
        System.out.println("in Exception2    "+ex.getMessage());
        ex.printStackTrace();
    }
    finally{

        System.out.println("in finally 2");
    }

}

在createPdf（）函数中，首次尝试块代码后既不运行也不抛出任何异常。