how can I get more specific font information use poi XWPF API? when I use one Calibri font file to test, the fontName I get is null and fontsize is -1

I use this code to test one Times New Roman font file and one Calibri font file. As for Times New Roman, the code can return the font name but not font size. As for Calibri, I can’t get either font name or font size. I don’t know what’s wrong happened…

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.List;

import org.apache.poi.xwpf.usermodel.XWPFDocument;
import org.apache.poi.xwpf.usermodel.XWPFParagraph;
import org.apache.poi.xwpf.usermodel.XWPFRun;

public class test1 {

    public static void main(String[] args) {
        File file = new File("F://workspace//zExtractInformationTest2//bold.docx");
        XWPFDocument document;
        try {
            document = new XWPFDocument(new FileInputStream(file));
            List<XWPFParagraph> paraList = document.getParagraphs();

            for (int index = 0; index < paraList.size(); index++) {
                XWPFParagraph para = paraList.get(index);
                for (XWPFRun run : para.getRuns()) {
                    String font = run.getFontName();
                    int fontSize = run.getFontSize();
                    String text = run.text();
                    boolean isBold = run.isBold();
                    System.out.println("run:        "+font+"/t"+fontSize+"/t"+text+"/t"+isBold);
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}