Parsing PDF file using Apache PDFBox to get outlines

Question

Now I can use the PDFBox to extract the outlines from PDF, but some PDF can get the outlines, others can't.

Every PDF has outlines and when I open a pdf use pdf read tool, I can click an outline to a certain page.

Here is my code:

public static void main(String[] args) {
     try {
        PDDocument document = PDDocument.load(new File(filePath));
        PDDocumentOutline outline = document.getDocumentCatalog().getDocumentOutline();
        getOutlines(document, outline, "");
        document.close();
    } catch (InvalidPasswordException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

public static void getOutlines(PDDocument document, PDOutlineNode bookmark, String indentation) throws IOException{
    PDOutlineItem current = bookmark.getFirstChild();
    while (current != null) {
        PDPage currentPage = current.findDestinationPage(document);
        Integer pageNumber = document.getDocumentCatalog().getPages().indexOf(currentPage) + 1;
        System.out.println(current.getTitle() + "-------->" + pageNumber);
        getOutlines(document, current, indentation);
        current = current.getNextSibling();
    }
}