the below code merges the pdf files and returns the combined pdf data. while this code runs, i try to combine the 100 files with each file approximately around 500kb, i get outofmemory error in the line document.close();. this code runs in the web environment, is the memory available to webspehere server is the problem? i read in an article to use freeReader method, but i cannot get how to use it my scenario.

protected ByteArrayOutputStream joinPDFs(List<InputStream> pdfStreams,
        boolean paginate) {

    Document document = new Document();

    ByteArrayOutputStream mergedPdfStream = new ByteArrayOutputStream();

    try {
        //List<InputStream> pdfs = pdfStreams;
        List<PdfReader> readers = new ArrayList<PdfReader>();
        int totalPages = 0;
        //Iterator<InputStream> iteratorPDFs = pdfs.iterator();
        Iterator<InputStream> iteratorPDFs = pdfStreams.iterator();

        // Create Readers for the pdfs.
        while (iteratorPDFs.hasNext()) {
            InputStream pdf = iteratorPDFs.next();
            if (pdf == null)
                continue;
            PdfReader pdfReader = new PdfReader(pdf);
            readers.add(pdfReader);
            totalPages += pdfReader.getNumberOfPages();
        }

        //clear this
        pdfStreams = null;

        //WeakReference ref = new WeakReference(pdfs);
        //ref.clear();

        // Create a writer for the outputstream
        PdfWriter writer = PdfWriter.getInstance(document, mergedPdfStream);
        writer.setFullCompression();

        document.open();
        BaseFont bf = BaseFont.createFont(BaseFont.HELVETICA,
                BaseFont.CP1252, BaseFont.NOT_EMBEDDED);
        PdfContentByte cb = writer.getDirectContent(); // Holds the PDF
        // data

        PdfImportedPage page;
        int currentPageNumber = 0;
        int pageOfCurrentReaderPDF = 0;
        Iterator<PdfReader> iteratorPDFReader = readers.iterator();

        // Loop through the PDF files and add to the output.
        while (iteratorPDFReader.hasNext()) {
            PdfReader pdfReader = iteratorPDFReader.next();

            // Create a new page in the target for each source page.
            while (pageOfCurrentReaderPDF < pdfReader.getNumberOfPages()) {
                pageOfCurrentReaderPDF++;
                document.setPageSize(pdfReader
                        .getPageSizeWithRotation(pageOfCurrentReaderPDF));
                document.newPage();
                // pageOfCurrentReaderPDF++;
                currentPageNumber++;
                page = writer.getImportedPage(pdfReader,
                        pageOfCurrentReaderPDF);
                cb.addTemplate(page, 0, 0);

                // Code for pagination.
                if (paginate) {
                    cb.beginText();
                    cb.setFontAndSize(bf, 9);
                    cb.showTextAligned(PdfContentByte.ALIGN_CENTER, ""
                            + currentPageNumber + " of " + totalPages, 520,
                            5, 0);
                    cb.endText();
                }
            }
            pageOfCurrentReaderPDF = 0;
            System.out.println("now the size is: "+pdfReader.getFileLength());
        }
        mergedPdfStream.flush();
        document.close();
        mergedPdfStream.close();
        return mergedPdfStream;
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        if (document.isOpen())
            document.close();
        try {
            if (mergedPdfStream != null)
                mergedPdfStream.close();
        } catch (IOException ioe) {
            ioe.printStackTrace();
        }
    }
    return mergedPdfStream;
}

Thanks V