import com.spire.pdf.PdfDocument;
import com.spire.pdf.bookmarks.PdfBookmark;
import com.spire.pdf.bookmarks.PdfTextStyle;
import com.spire.pdf.graphics.PdfRGBColor;

import java.awt.*;

public class EditBookmarks {
    public static void main(String[] args) {
        //Create a PdfDocument instance
        PdfDocument doc = new PdfDocument();
        //Load the PDF file
        doc.loadFromFile("Bookmarks.pdf");

        //Get the first bookmark
        PdfBookmark bookmark = doc.getBookmarks().get(0);
        //Change the title of the bookmark
        bookmark.setTitle("New Title");
        //Change the font color of the bookmark
        bookmark.setColor(new PdfRGBColor(new Color(255,0,0)));
        //Change the outline text style of the bookmark
        bookmark.setDisplayStyle(PdfTextStyle.Italic);

        //Edit child bookmarks of the first bookmark
        for (PdfBookmark childBookmark : (Iterable<PdfBookmark>) bookmark {
            childBookmark.setColor(new PdfRGBColor(new Color(0,0,255)));
            childBookmark.setDisplayStyle(PdfTextStyle.Bold);

            for (PdfBookmark childBookmark2 : (Iterable<PdfBookmark>) bookmark {
                childBookmark2.setColor(new PdfRGBColor(new Color(160,160,122)) );
                childBookmark2.setDisplayStyle(PdfTextStyle.Bold);
            }
        }

        //Save the result file
        doc.saveToFile("EditBookmarks.pdf");
        doc.close();
    }
}