How to edit a PDF file and conformance level (PDF/A)

[Ber1984]

Hello I have the requirement to edit an existing PDF and add a conformance level (PDF/A)

For example I have this pdf file.

otrosi.pdf
and I need to edit it and add PDF/A conformance.

I'm trying doing this but not working yet

 PdfReader reader = new PdfReader(getFileFromResourceAsStream("templates/test_release.pdf"));

        PdfStamper stamper = new PdfStamper(reader, new FileOutputStream("updated-meta-data.pdf"));

        // update xmp meta-data
        ByteArrayOutputStream baos = new ByteArrayOutputStream();

        XmpWriter xmp = new XmpWriter(baos, new PdfDictionary(), PdfWriter.PDFA1B);
        xmp.close();

        stamper.setXmpMetadata(baos.toByteArray());
        stamper.close();
        reader.close();

Any idea how to do it?

[asturio]

Take a look at:
com.lowagie.examples.conformance.PdfA1B