I am using JasperReports to generate PDF documents and attempting to validate them with the Mustang library via

ZUGFeRDValidator validator = new ZUGFeRDValidator();
return validator.validate("./mypdf.pdf");

However, I encounter the following error: "A CIDSet entry in the Font descriptor does not correctly identify all glyphs present in the embedded font subset."

I am using the following libraries:

• JasperReports Version: 6.21.3
• Mustang Validator Version: 2.11.0
• PDFBox Version: 3.0.2

Here is the code I use to create pdfs:

generate(JasperReport report, Map<String,Object> data) {
            [...]
            JasperPrint print = JasperFillManager.fillReport(report, data, new JREmptyDataSource());
            JRPdfExporter exporter = new JRPdfExporter();
            exporter.setExporterInput(new SimpleExporterInput(print));
            exporter.setExporterOutput(new SimpleOutputStreamExporterOutput(document));

            SimplePdfExporterConfiguration exportConfig = new SimplePdfExporterConfiguration();
            exportConfig.setPdfVersion(PdfVersionEnum.VERSION_1_7);
            exportConfig.setPdfaConformance(PdfaConformanceEnum.PDFA_3B);
            exportConfig.setIccProfilePath("AdobeRGB1998.icc");
            exportConfig.setMetadataAuthor("Your Name");
            exportConfig.setTagged(true);
            exportConfig.setTagLanguage("en-us");
            exportConfig.setEmbedIccProfile(true);

            exporter.setConfiguration(exportConfig);
            exporter.exportReport();

            [...]
}

The fonts that I’m using are OpenSans fonts:

In my fontsfamily.xml:

<?xml version="1.0" encoding="UTF-8"?>
<fontFamilies>
    <fontFamily name="OpenSans">
        <!-- Normal Font -->
        <normal><![CDATA[fonts/OpenSans-Regular.ttf]]></normal>
        <!-- Bold Font -->
        <bold><![CDATA[fonts/OpenSans-Bold.ttf]]></bold>
        <!-- Italic Font -->
        <italic><![CDATA[fonts/OpenSans-Italic.ttf]]></italic>
        <!-- Bolt italic Font -->
        <boldItalic><![CDATA[fonts/OpenSans-BoldItalic.ttf]]></boldItalic>
        <!-- Is font is embedded in PDF -->
        <pdfEmbedded><![CDATA[true]]></pdfEmbedded>
    </fontFamily>
</fontFamilies>

In my jasperreports_extension.properties:

net.sf.jasperreports.extension.registry.factory.fonts=net.sf.jasperreports.engine.fonts.SimpleFontExtensionsRegistryFactory
net.sf.jasperreports.extension.simple.font.families.OpenSans=fonts/fontsfamily.xml

I suspected that there might be an issue with how I embed the font, so here are my attempts:

• I have ensured that the fonts are embedded as subsets by using the isPdfEmbedded attribute like this:

<style name="Standard" isDefault="true" pattern="" fontName="OpenSans" fontSize="10" isPdfEmbedded="true"/>

The pdf acrobat reader also shows in the font properties that a subset of the font is embedded.

• The error also occurs when I comment out all text from the .jrxml report template, leaving only the font styles embedded.

• I tried out another font as well (DejaVu Sans), to see if OpenSans is the problem but it didn’t work either.

I know that the error is related to a CIDSet, but it seems that it is implicit which I might have no control of?

What else can I do?