Why does PdfStamper create a file with 0 bytes?

When attempting to encrypt a pdf, I get a zero size file as a result. Any ideas what is causing this?

File f = new File("C://secure_abc.pdf");
FileOutputStream out = new FileOutputStream(f);
PdfReader reader = new PdfReader("C://abc.pdf");
System.out.println("reader.getFileLength(): "+reader.getFileLength());
PdfStamper stamp = new PdfStamper(reader, out);
stamp.setEncryption(null, null,
    PdfWriter.ALLOW_PRINTING, PdfWriter.ENCRYPTION_AES_128);

Posted on StackOverflow on Jul 8, 2014 by integratedsolns

In iText 7 all manipulations with PDF are done using PdfDocument instance. Encryption can be done like this:

PdfReader reader = new PdfReader(src);
WriterProperties props = new WriterProperties()
        .setStandardEncryption("Hello".getBytes(), "World".getBytes(), EncryptionConstants.ALLOW_PRINTING,
                EncryptionConstants.ENCRYPTION_AES_128 | EncryptionConstants.DO_NOT_ENCRYPT_METADATA);
PdfWriter writer = new PdfWriter(new FileOutputStream(dest), props);
PdfDocument pdfDoc = new PdfDocument(reader, writer);
pdfDoc.close();

The problem you were faced with was about not closing PdfStamper. Don't forget to close the PdfDocument instance from now on.

Click this link if you want to see how to answer this question in iText 5.