Como concatenar as paginas de um pdf?

/*
 * $Id: Concatenate.java 2441 2006-10-27 17:24:01Z xlv $
 * $Name$
 *
 * This code is free software. It may only be copied or modified
 * if you include the following copyright notice:
 *
 * This class by Mark Thompson. Copyright (c) 2002 Mark Thompson.
 *
 * This code is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 */

/**
 * This class demonstrates copying a PDF file using iText.
 * @author Mark Thompson
 */
package com.lowagie.examples.general.copystamp;

import java.io.FileOutputStream;
import java.util.ArrayList;
import java.util.List;

import com.lowagie.text.Document;
import com.lowagie.text.pdf.PRAcroForm;
import com.lowagie.text.pdf.PdfCopy;
import com.lowagie.text.pdf.PdfImportedPage;
import com.lowagie.text.pdf.PdfReader;
import com.lowagie.text.pdf.SimpleBookmark;

/**
 * Tool that can be used to concatenate existing PDF files.
 */
public class Concatenate {

    /**
     * This class can be used to concatenate existing PDF files.
     * (This was an example known as PdfCopy.java)
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        if (args.length < 2) {
            System.err.println("arguments: file1 [file2 ...] destfile");
        }
        else {
        	System.out.println("PdfCopy example");
            try {
                int pageOffset = 0;
                ArrayList master = new ArrayList();
                int f = 0;
                String outFile = args[args.length-1];
                Document document = null;
                PdfCopy  writer = null;
                while (f < args.length-1) {
                    // we create a reader for a certain document
                    PdfReader reader = new PdfReader(args[f]);
                    reader.consolidateNamedDestinations();
                    // we retrieve the total number of pages
                    int n = reader.getNumberOfPages();
                    List bookmarks = SimpleBookmark.getBookmark(reader);
                    if (bookmarks != null) {
                        if (pageOffset != 0)
                            SimpleBookmark.shiftPageNumbers(bookmarks, pageOffset, null);
                        master.addAll(bookmarks);
                    }
                    pageOffset += n;
                    
                    if (f == 0) {
                        // step 1: creation of a document-object
                        document = new Document(reader.getPageSizeWithRotation(1));
                        // step 2: we create a writer that listens to the document
                        writer = new PdfCopy(document, new FileOutputStream(outFile));
                        // step 3: we open the document
                        document.open();
                    }
                    // step 4: we add content
                    PdfImportedPage page;
                    for (int i = 0; i < n; ) {
                        ++i;
                        page = writer.getImportedPage(reader, i);
                        writer.addPage(page);
                    }
                    PRAcroForm form = reader.getAcroForm();
                    if (form != null)
                        writer.copyAcroForm(reader);
                    f++;
                }
                if (!master.isEmpty())
                    writer.setOutlines(master);
                // step 5: we close the document
                document.close();
            }
            catch(Exception e) {
                e.printStackTrace();
            }
        }
    }
}

PdfReader reader = new PdfReader("c://manual_APD_operacional.pdf");
	    		    	         // n recebe o numero total de páginas
	    		    	         int n = reader.getNumberOfPages();
	    		    	         // tamanho da primeira página
	    		    	         Rectangle psize = reader.getPageSize(1);
	    		    	         float width = psize.getHeight();
	    		    	         float height = psize.getWidth();

	    		    	         // cria segundo pdf
	    		    	         Document document = new Document(new Rectangle(width, height));
	    		    	         PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream("C://SegundoPDF.pdf"));
	    		    	         document.open();
	    		    	         // adiciona conteudo ao segundo pdf
	    		    	         PdfContentByte cb = writer.getDirectContent();
	    		    	         int i = 0;
	    		    	         int p = 0;
	    		    	         while (i < n) {
	    		    	            document.newPage();
	    		    	            p++;
	    		    	            i++;
	    		    	            PdfImportedPage page1 = writer.getImportedPage(reader, i);
	    		    	            cb.addTemplate(page1, .5f, 0, 0, .5f, 60, 120);
	    		    	            if (i < n) {
	    		    	               i++;
	    		    	               PdfImportedPage page2 = writer.getImportedPage(reader, i);
	    		    	               cb.addTemplate(page2, .5f, 0, 0, .5f, width / 2 + 60, 120);
	    		    	            }
	    		    	            
	    		    	            BaseFont bf = BaseFont.createFont(BaseFont.HELVETICA, BaseFont.CP1252, BaseFont.NOT_EMBEDDED);
	    		    	            //adiciono texto no rodapé 
	    		    	            cb.beginText();
	    		    	            cb.setFontAndSize(bf, 14);
	    		    	            Date d = new Date();
	    		    	          
	    		    	            
	    		    	            cb.showTextAligned(PdfContentByte.ALIGN_CENTER, "Konsultex "+fdata2.format(d),  width / 2, 40, 0);
	    		    	            cb.endText();
	    		    	         }
	    		    	         
	    		    	         document.close();

JFrame frame = new JFrame("PDF Test");
        jScrollPane1 = new JScrollPane();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        ImageIcon img2 = new ImageIcon(img);
        
 	   frame.add(jScrollPane1, BorderLayout.CENTER);
 	   {
 		   label = new JLabel();  
 		   jScrollPane1.setViewportView(label);
 		   label.setIcon( img2 );
 	   }
       // frame.add(new JLabel(new ImageIcon(img)));
        frame.pack();
        frame.setVisible(true);
        frame.setSize(img2.getIconWidth(),600); 
        frame.setBounds(50, 50, img2.getIconWidth(),600);