Blank PDF while converion from HTML(Email Body)

Aspose.PDF Product Family
1

We have paid support on Aspose.Java , The issue blank PDF occurs while we are converting from HTML(email body) to PDF , as an application, we have increased the Memory, but the issue occuring 2 twice a month

2

@phaneendra.sa

You are seeing an intermittent blank PDF when the HTML that represents an e‑mail body is rendered with Aspose.PDF for Java. The problem persists even after increasing the JVM heap, and it occurs only a few times per month — this pattern is typical of a resource‑related edge case inside the HTML‑to‑PDF conversion pipeline [1].

Likely causes

Cause Why it can produce a blank PDF
Large or complex HTML (embedded images, CSS, tables) that forces the renderer to allocate temporary buffers larger than the available native memory. When the allocation fails the renderer silently produces an empty page.
Concurrent conversions in the same JVM. The internal native libraries used by Aspose.PDF are not fully thread‑safe for simultaneous HTML loads, which can lead to occasional blank output.
Out‑of‑date library. Several memory‑optimisation bugs were fixed in recent releases (e.g., 22.9 → 23.3). Using an older version can trigger the symptom you described.

Immediate work‑arounds

  1. Upgrade to the latest Aspose.PDF for Java version – all known memory‑leak and blank‑page issues have been addressed in the most recent builds.

  2. Load the HTML with explicit options so the renderer can pre‑allocate the required resources:

    // htmlString contains the e‑mail body
HtmlLoadOptions loadOptions = new HtmlLoadOptions();
loadOptions.setPageSize(PageSize.A4);
loadOptions.setFontEmbeddingMode(FontEmbeddingMode.EmbedAll);
loadOptions.setMemoryOptimization(true);   // reduces native memory pressure

PdfDocument pdf = new PdfDocument();
pdf.bindHtml(htmlString, loadOptions);
pdf.save("output.pdf");

    setMemoryOptimization(true) forces the engine to use a streaming approach instead of loading the whole DOM into native memory, which mitigates intermittent blank pages.

  3. Serialize conversions – if your application processes many e‑mails in parallel, serialize the bindHtml calls (e.g., via a single‑threaded executor) or create a separate JVM instance per conversion. This eliminates the rare race condition that can leave the output empty.

  4. Enable detailed logging to capture the exact moment the renderer fails:

    Logger logger = Logger.getLogger("com.aspose.pdf");
logger.setLevel(Level.FINE);
// add a FileHandler to persist the log

    The log will contain messages such as “HTML rendering failed – insufficient native memory”, which can be attached to a support case if the problem persists.

If the issue remains

Collect the following information and open a dedicated support ticket (you already have paid support, so you can reference this thread):

  • Exact Aspose.PDF for Java version and JVM version.
  • Sample HTML that reproduces the blank PDF (including any embedded images or CSS).
  • Heap and native memory statistics at the time of conversion (e.g., Runtime.getRuntime().totalMemory() / freeMemory()).
  • Log file generated with Level.FINE as shown above.

Providing these details will allow the Aspose development team to reproduce the edge case and, if it is a regression, log it for a future fix.

Feel free to share a minimal reproducible example here; we can run it in our sandbox to confirm the behaviour and suggest a more targeted fix.

3

Thanks for suggestions , we have the latest version of aspose 25.10 ,and will try increase to 25.11 and will add Level.fine log and setMemoryOptimization , and our system process all operation of read of Graph API email to converting pdf in single thread

4

@phaneendra.sa

The intermittent blank PDF you see is a known edge‑case in the HTML‑to‑PDF pipeline of Aspose.PDF for Java. It is usually triggered when the native renderer runs out of memory or when several conversions are executed concurrently in the same JVM – both situations can cause the engine to finish the conversion without rendering any page [1].

Why it happens

Reason Effect
Large/complex HTML (embedded images, CSS, tables) The renderer allocates native buffers that may exceed the available native memory; on failure it silently produces an empty document.
Concurrent conversions in one JVM The native libraries are not fully thread‑safe for simultaneous bindHtml calls, leading to occasional blank output.
Older library version Several memory‑optimisation bugs were fixed in recent releases; using a version prior to the fix can reproduce the symptom.

Immediate actions that usually eliminate the problem

  1. Upgrade to the newest build (e.g., 25.11). All known memory‑leak and blank‑page issues have been addressed in the latest releases [1].

  2. Enable memory‑optimised HTML loading.

    String html = ...;                     // e‑mail body
HtmlLoadOptions loadOptions = new HtmlLoadOptions();
loadOptions.setPageSize(PageSize.A4);
loadOptions.setFontEmbeddingMode(FontEmbeddingMode.EmbedAll);
loadOptions.setMemoryOptimization(true);   // streaming mode
PdfDocument pdf = new PdfDocument();
pdf.bindHtml(html, loadOptions);
pdf.save("output.pdf");

    setMemoryOptimization(true) forces the engine to use a streaming approach instead of loading the whole DOM into native memory, which mitigates the blank‑page symptom [1].

  3. Serialize conversions (single‑threaded executor or separate JVM per conversion). If your service processes many e‑mails, ensure that only one bindHtml runs at a time; this removes the rare race condition that can leave the output empty [1].

  4. Increase JVM heap and native memory limits (e.g., -Xmx4g or higher) to give the native renderer enough room for large HTML payloads [1].

  5. Enable fine‑grained logging to capture the exact point of failure:

    java.util.logging.Logger logger = java.util.logging.Logger.getLogger("com.aspose.pdf");
logger.setLevel(java.util.logging.Level.FINE);

    The generated log will contain messages from the native renderer that can be attached to a support case if the issue persists [1].

If the problem continues after the steps above

  • Collect the Level.FINE log file.
  • Record the HTML snippet that caused the blank PDF (if possible).
  • Provide the exact JVM options and memory settings you are using.

With those details we can reproduce the failure and, if it turns out to be a regression, log it for a fix.

5

loadOptions.setMemoryOptimization(true); is not available in PDF HtmlLoadOptions i have latest of 25.12 version of ASPOSE.PDF

6

@phaneendra.sa
Could you share the sample of file that produces such blank PDF?

8

It is not about a specific document, so if this issue start, it is happening to all document, so it looks like resource /memory issue from aspose

9

a { text-decoration: none; color: #464feb; } tr th, tr td { border: 1px solid #e6e6e6; } tr th { background-color: #f5f5f5; }

— setMemoryOptimization is not a member of HtmlLoadOptions in Aspose.PDF.
That flag exists in Aspose.Words (SaveOptions.MemoryOptimization) and is unrelated to Aspose.PDF’s HTML ingestion pipeline. from copilt , is that correct

10

will this below thing help , options.setRenderToSinglePage(false);

document.optimize();

			// 3) Deep resource optimization
			OptimizationOptions opt = new OptimizationOptions();
			opt.setRemoveUnusedObjects(true);
			opt.setRemoveUnusedStreams(true);
			opt.setLinkDuplicateStreams(true);
			opt.setSubsetFonts(true); // trim font tables
			opt.setAllowReusePageContent(true);

			// Optional: image compression/downsampling (if your HTML has big rasters)
			ImageCompressionOptions img = opt.getImageCompressionOptions();
			img.setCompressImages(true);
			img.setImageQuality(85); // trade-off: 60–85 commonly good
			img.setMaxResolution(200); // downsample high-DPI images

			document.optimizeResources(opt);
11

@phaneendra.sa
This is about optimizing document and I’m not sure if it helps with problem you have described - optimizing usually takes additional time and resources in document processing. You can try though, maybe it would help in some unexpected way
Could you also share the code you’re using for processing documents?
Maybe there will be something to hint where the problem could be

12

public void processedEmailContent(com.microsoft.graph.models.Message msg, ByteArrayOutputStream os, String data)
throws ParseException, Exception, IOException {

	  FontRepository.getSources().add(new FolderFontSource(timesNewRomanFront));
        java.io.InputStream htmlStream = new java.io.ByteArrayInputStream(data.getBytes());

	PageInfo pageInfo = new PageInfo();
	pageInfo.setWidth(595); // A4 width
	pageInfo.setHeight(842); // A4 height

	pageInfo.getMargin().setTop(36); // 0.5 inch
	pageInfo.getMargin().setBottom(36);
	pageInfo.getMargin().setLeft(36);
	pageInfo.getMargin().setRight(36);

        // Load HTML from stream
	HtmlLoadOptions options = new HtmlLoadOptions();
	options.setPageInfo(pageInfo);
       // options.setInputEncoding("UTF-8");
	options.setRenderToSinglePage(false);
	
        options.setEmbedFonts(true);
       try (Document document = new Document(htmlStream, options)) {
			// Save as PDF

			document.optimize();

			// 3) Deep resource optimization
			OptimizationOptions opt = new OptimizationOptions();
			opt.setRemoveUnusedObjects(true);
			opt.setRemoveUnusedStreams(true);
			opt.setLinkDuplicateStreams(true);
			opt.setSubsetFonts(true); // trim font tables
			opt.setAllowReusePageContent(true);

			// Optional: image compression/downsampling (if your HTML has big rasters)
			ImageCompressionOptions img = opt.getImageCompressionOptions();
			img.setCompressImages(true);
			img.setImageQuality(85); // trade-off: 60–85 commonly good
			img.setMaxResolution(200); // downsample high-DPI images

			document.optimizeResources(opt);

		for (Page page : document.getPages()) {
			TextFragmentAbsorber absorber = new TextFragmentAbsorber();
			page.accept(absorber);

			for (TextFragment fragment : absorber.getTextFragments()) {
				// logger.info("before font"+fragment.getTextState().getFont().getFontName());
				// fragment.getTextState().setFont(FontRepository.openFont(timesNewRomanFront));
				// logger.info("a font"+fragment.getTextState().getFont().getFontName());

				String text = fragment.getText();
				if (text.length() > 1000) {
					logger.info("data-->" + text);

					fragment.setText("");
					TextFragment newFragment = new TextFragment(insertNewlines(text, 85));
					newFragment.getTextState().setFontSize(fragment.getTextState().getFontSize());
					newFragment.getTextState().setFont(fragment.getTextState().getFont());

					// Position new text slightly below original
					Position newPos = new Position(fragment.getPosition().getXIndent(),
							fragment.getPosition().getYIndent());
					newFragment.setPosition(newPos);

					// Add new fragment to page
					fragment.getPage().getParagraphs().add(newFragment);

					logger.info("data-change-->" + newFragment.getText());
				}
			}

		}
			document.save(os);
		}				
	

}
13

@phaneendra.sa
Thank you for provided information. I’ll add task for development team with this information to investigate how to solve this problem

14

@phaneendra.sa
We have opened the following new ticket(s) in our internal issue tracking system and will deliver their fixes according to the terms mentioned in Free Support Policies.

Issue ID(s): PDFNET-61497

You can obtain Paid Support Services if you need support on a priority basis, along with the direct access to our Paid Support management team.

15

we have paid license with the "Aspose Order Number "for ASPOSE.ALL JAVA , how can we get paid support

16

@phaneendra.sa
You can obtain details about that going through the link Paid Support Services

17

could you please help to get credentials? for that

18

@phaneendra.sa
Unfortunately it’s separate forum and it’s not available for Free Forum moderators.
Maybe there was some information with ordered license?

19

Hi Could you please help with the status of the issue, as we are facing the same issue again.

20

we adeed but no detials in logs

21

name=“com.aspose.pdf” level="FINE