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Comparing PDF documents returns null in Java

I am evaluating GroupDocs.Compare for Java. I have a temporary license and it was working fine for the documents I was comparing. I have compared a number of PDFs without a problem. However, PDFs coming out of our current production system always cause a null result to come back from compare. No exceptions, no errors, just a null return object. I can’t figure out what is different with these PDFs. They are PDF 1.5 with no security, just like the ones that do compare. I will attach a zip file with two PDFs that fail to compare.

I can’t find a link to attach files.


Thanks for taking interest in GroupDocs.Comparison for Java and posting your concerns.
In order to investigate this issue at our end, we need following details:

  • Which version (e.g. 17.3.2, 17.1) of the API you integrated in the project?
  • Share problematic PDFs with us

Please see this screenshot How to attach.JPG (2.4 KB). It’ll help you in uploading the files.

I am using 17.3.2. I have attached a zip file with two (78.3 KB)


This issue is reproduced at our end. Hence, it has been logged in our internal issue tracking system with ID: COMPARISONJAVA-418. As we have any update on it, you shall be notified.

Thanks for the update.


You’re welcome.

I have some additional information about the PDFs that don’t work and the PDFs that do. The PDFs that do not work were created by Aspose.Words 13.5.0 and the ones that do work were created with Aspose.Words 16.8.0. These came from two different releases of our software which uses Aspose for document creation and conversion. Both releases are still supported at this time and we are looking at a way for our clients to compare documents between releases for regression testing.


Thanks for the elaboration.
We are further investigating this at our end. As we have further updates on it, we shall let you know.


Your reported issue COMPARISONJAVA-418 is resolved in 18.6 version of the API. Please integrate latest release of the API in your project. If the issue persists, let us know.

I downloaded and testing version 18.6 and it is now returning a result object and producing a report. This case can be closed.


Good to know that this issue is now resolved.