Question

Java 画线

import javax.swing.*;
import java.awt.*;
class Jframe extends JFrame{
public Jframe(){
//setBounds(100,100,200,300);
this.setSize(400,300);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
}
@Override
public void paint(Graphics g) {
super.paint(g);
g.drawLine(40,40,40,250);
g.drawLine(40,250,300,250);
}

}
public class myDraw {
public static void main (String args[]) {
try{
new Jframe();
}catch(Exception e){
e.printStackTrace();
}

}
}
错误提示
java.lang.NoSuchMethodError: main
Exception in thread "main"
Process completed.
为什么有时能通过有时就报这错呢？

Answer 1

import javax.swing.*;
import java.awt.*;
class Jframe extends JFrame{
public Jframe(){
//setBounds(100,100,200,300);
this.setSize(400,300);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
}
@Override
public void paint(Graphics g) {
super.paint(g);
g.drawLine(40,40,40,250);
g.drawLine(40,250,300,250);
}

}
public class myDraw {
public static void main (String args[]) {
//try{
new Jframe();
//}catch(Exception e){
//e.printStackTrace();
//}

}
}