code: public PdfImportedPage getImportedPage(PdfReader reader, int pageNumber) {
          if (currentPdfReaderInstance != null) {
              if (currentPdfReaderInstance.getReader() != reader) {
                  try {
                      currentPdfReaderInstance.getReader().close();
                      currentPdfReaderInstance.getReaderFile().close();
                  }
                  catch (IOException ioe) {
                      // empty on purpose
                  }
                  currentPdfReaderInstance = reader.getPdfReaderInstance(this);
              }
          }
          else {
              currentPdfReaderInstance = reader.getPdfReaderInstance(this);
          }
          return currentPdfReaderInstance.getImportedPage(pageNumber);            
      }
docs: Grabs a page from the input document
  @param reader the reader of the document
  @param pageNumber which page to get
  @return the page