Java Swing - 如何从JFileChooser获得文件类型描述

import java.io.File;

import javax.swing.JFileChooser;

public class Main {
  public static void main(String[] args) {
    File f = new File("f.jpg");
    JFileChooser j = new JFileChooser();
    System.out.println(j.getTypeDescription(f));
  }
}