Itext com JSF

PdfReader r = null;
		byte[] b = null;
		ByteArrayInputStream bais = new ByteArrayInputStream("Rodrigo".getBytes());
		ByteArrayOutputStream baos = new ByteArrayOutputStream();
		    r = new PdfReader(bais);
			PdfStamper stamper = new PdfStamper(r,baos);
			PdfContentByte over = stamper.getOverContent(1);
			Image img = Image.getInstance("C:\\logo.bmp");
			img.setAbsolutePosition(5, 5);
			PdfContentByte under;
			int total = r.getNumberOfPages() + 1;
			for (int i = 1; i < total; i++) {
			under = stamper.getUnderContent(i);
			under.addImage(img);
			}
			stamper.close();

Exception in thread “main” java.io.IOException: PDF header signature not found.

at com.lowagie.text.pdf.PRTokeniser.checkPdfHeader(Unknown Source)

at com.lowagie.text.pdf.PdfReader.readPdf(Unknown Source)

at com.lowagie.text.pdf.PdfReader.(Unknown Source)

at com.lowagie.text.pdf.PdfReader.(Unknown Source)

at teste.main(teste.java:29)