建立框架窗口并输出语句

import java.awt.*;import java.awt.event.*;public class train1_2 extends Frame {   Label lHello;   public train1_2()   {   lHello=new Label("Hello,Java World!");   add(lHello);      addWindowListener (new WindowAdapter(){   public void windowClosing(WindowEvent e){   System.exit(0);   }   });   setSize(160,60);   setVisible(true);   }public static void main(String[] args) {train1_2 hello=new train1_2();}}