Loosing Borkmars while merging pdfs

Hi,

We are trying to replace a different product jar file with aspose and we are left with just one item that is bookmarks - creating and preserving them but when I am using the following code to add bookmarks to an existing pdf file. The issue is it creates a parent bookmark as bookmark 0 but only creates 2 child as child bookmark 2 and 3. Below is the image how it is creating.



com.aspose.pdf.Document pdfDocument = new com.aspose.pdf.Document("C:\\documents\\testdata\\GI_3a8b4e21-2063-40ec-8b6c-7daa2bfc2fac.pdf");
       
        PdfBookmarkEditor bookmarkEditor = new PdfBookmarkEditor();
        bookmarkEditor.bindPdf(pdfDocument);

        com.aspose.pdf.OutlineItemCollection parentOutline = new com.aspose.pdf.OutlineItemCollection(pdfDocument.getOutlines());
        // Extract bookmarks
        Bookmarks bookmarks = bookmarkEditor.extractBookmarks();
        com.aspose.pdf.facades.Bookmarks childList = new com.aspose.pdf.facades.Bookmarks();
       
        for(int i = 0; i < 3; i++)
        {
            Bookmark bookMark = new Bookmark();
           
            bookMark.setPageNumber(i);
            bookMark.setTitle("Parent Bookmark " + i);
            bookMark.setLevel(1);
           
            for (int j = 0; j < 4; j++)
            {   
                com.aspose.pdf.facades.Bookmark bookmark2 = new     com.aspose.pdf.facades.Bookmark();
                bookmark2.setPageNumber(1);
                bookmark2.setTitle("child bookmark " + j);
                bookmark2.setLevel(2);
               
                childList.add(bookmark2);
            }
           
            bookMark.setChildItem(childList);
       
            bookmarkEditor.createBookmarks(bookMark);
        }
       
        bookmarkEditor.save("C:\\users\\mathurrk\\bookEdit.pdf");

Thanks in advance.