firstgui.java

《A first book of java》by Gary J.Bronson 北大出版社

import javax.swing.*;
public class FirstGui
{
  public static void main(String args[])
  {
    JFrame mainFrame; // declare a JFrame reference variable
    mainFrame = new JFrame("First GUI Window"); //instantiate a JFrame object

    mainFrame.setSize(300,150);
    mainFrame.show(); 
  }
}