@Override
    protected PdfDictionary getCatalog(PdfIndirectReference rootObj) {
        try {
            PdfDictionary cat = pdf.getCatalog(rootObj);
            if (form != null) {
                PdfIndirectReference ref = addToBody(form).getIndirectReference();
                cat.put(PdfName.ACROFORM, ref);
            }
            return cat;
        }
        catch (IOException e) {
            throw new ExceptionConverter(e);
        }
    }