This sample removes the Collection dictionary from a PDF Portfolio making it a regular PDF file with attachments.

UnPortfolio.java

/*
 * Copyright Datalogics, Inc. 2015
 */

package pdfjt.cookbook.document;

import com.adobe.internal.io.ByteReader;
import com.adobe.internal.io.InputStreamByteReader;
import com.adobe.pdfjt.core.types.ASName;
import com.adobe.pdfjt.pdf.document.PDFCatalog;
import com.adobe.pdfjt.pdf.document.PDFDocument;
import com.adobe.pdfjt.pdf.document.PDFFileSpecification;
import com.adobe.pdfjt.pdf.document.PDFNameDictionary;
import com.adobe.pdfjt.pdf.document.PDFNamedEmbeddedFiles;
import com.adobe.pdfjt.pdf.document.PDFOpenOptions;
import com.adobe.pdfjt.pdf.interactive.navigation.collection.PDFCollectionItem;
import com.adobe.pdfjt.pdf.interactive.navigation.collection.PDFCollectionItemData;
import com.adobe.pdfjt.pdf.interactive.navigation.collection.PDFCollectionSubItem;
import com.adobe.pdfjt.pdf.page.PDFPageMode;
import com.adobe.pdfjt.services.manipulations.PMMService;
import com.datalogics.pdf.document.DocumentHelper;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;
import java.util.Iterator;

/**
 *  This sample removes the Collection dictionary from a PDF Portfolio making it a regular PDF file with attachments.
 */
public class UnPortfolio {

    private static final String inputPDFURL = "http://dev.datalogics.com/cookbook/portfolios/portfolio-sample.pdf";
    private static final String coverPDFURL = "http://dev.datalogics.com/cookbook/portfolios/DL_coversheet.pdf";
    private static final String outputDir = "cookbook/Document/output/";

    static public void main(String[] args) throws Exception {

        // First read in the two PDF files we need. The Portfolio source and
        // then the new cover sheet. The cover sheet will be the file that
        // displayed when the PDF is opened.
        URLConnection connection = new URL(inputPDFURL).openConnection();
        connection.setRequestProperty("User-Agent",
                "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.95 Safari/537.11");
        connection.connect();
        InputStream fis = connection.getInputStream();
        ByteReader byteReader = new InputStreamByteReader(fis);
        PDFDocument pdfDocument = PDFDocument.newInstance(byteReader, PDFOpenOptions.newInstance());

        connection = new URL(coverPDFURL).openConnection();
        connection.setRequestProperty("User-Agent",
                "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.95 Safari/537.11");
        connection.connect();
        fis = connection.getInputStream();
        ByteReader coverSheetByteReader = new InputStreamByteReader(fis);
        PDFDocument coverSheetDocument = PDFDocument.newInstance(coverSheetByteReader, PDFOpenOptions.newInstance());

        // Get the PDF Catalog
        PDFCatalog pdfCatalog = pdfDocument.requireCatalog();
        if (pdfCatalog.getCollection() != null) {
            // If the Collection dictionary is present, remove it.
            pdfCatalog.removeValue(ASName.k_Collection);

            // Set the Page Mode to display the attachments panel if the viewer
            // supports it.
            pdfCatalog.setPageMode(PDFPageMode.WithAttachments);

            // Insert the new cover sheet then delete the original
            PMMService pmmService = new PMMService(pdfDocument);
            pmmService.appendPages(coverSheetDocument, null, null);
            pmmService.deletePages(pdfDocument.requirePages().getPage(0), 1);
            /*
             * This section of the code is optional. The PDF Portfolio templates
             * that come with Adobe Acrobat contain a "Summary" field that is
             * generally used to enter a description of the file attachment. In
             * this section we copy that data to the Description metadata field
             * for the attachment so it can be seen in the Acrobat Attachments
             * panel.
             */
            PDFNameDictionary pdfNameDictionary = pdfCatalog.getNameDictionary();
            PDFNamedEmbeddedFiles pdfNamedEmbeddedFiles = pdfNameDictionary.getNamedEmbeddedFiles();
            Iterator pdfNamedEmbeddedFilesIterator = pdfNamedEmbeddedFiles.iterator();
            while (pdfNamedEmbeddedFilesIterator.hasNext()) {
                PDFNamedEmbeddedFiles.Entry curEntry = (PDFNamedEmbeddedFiles.Entry) pdfNamedEmbeddedFilesIterator.next();
                PDFFileSpecification pdfFileSpecification = curEntry.getValue();
                // Get the Collection Item (CI) dictionary
                PDFCollectionItem pdfCollectionItem = pdfFileSpecification.getCollectionItem();
                String description;
                if (pdfCollectionItem != null) {
                    /*
                     * Get the data or string in the Summary field. It could be
                     * a string or a dictionary that contains the pure string
                     * and a rich text representation.
                     */
                    PDFCollectionSubItem summaryItem = pdfCollectionItem.getSubItem(ASName.create("adobe:Summary"));
                    PDFCollectionItemData summaryItemData = summaryItem.getData();
                    if (summaryItemData.isText() == false) {
                        description = summaryItem.getDictionaryTextStringOrStreamValue(ASName.k_D);
                    } else {
                        description = summaryItem.toString();
                    }
                    // Set the description
                    pdfFileSpecification.setDescription(description);
                    // Remove the Collection Information since it will no longer be used.
                    pdfFileSpecification.setCollectionItem(null);
                }
            }

        }
        // Save and close
        DocumentHelper.saveFullAndClose(pdfDocument, outputDir + "Not_A_Portfolio.pdf");

        // Save the file.
        System.out.println("Done!");
    }
}