Java GUI ：Hello World

public class Demo01 extends Frame{

public Demo01(){
super("Demo01");//标题
this.setSize(450, 500);//窗口的大小
this.setLocation(100,100);//窗口距离屏幕的距离
this.setVisible(true);
this.addWindowListener(new WindowAdapter() {//点击关闭按钮可以关闭程序
@Override
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
}

public static void main(String[] args) {
new Demo01();
}
}