JFrame applications problem

Question

Hi, i'm just starting out writing swing applications and i'm having a few problems.
Don't bother answering this if you think i'm too stupid because i don't want to waste your time.
Whenever i write a swing application, it compiles but when i try to run it i get: <b>Exception in thread "main" java.lang.NoSuchMethodError: main</b>
Heres my code:
<code>
import java.awt.*;
import javax.swing.*;
public class swingframe extends JFrame
     private JButton but;
     public swingframe()
               Container c=getContentPane();
               c.setLayout(new FlowLayout(FlowLayout.LEFT, 5, 5));
               c.setBackground(Color.black);
               but = new JButton("Wyld Stallyns Rule!!!");
               but.setBackground(Color.green);
               c.add(but);
</code>
Sorry again if i'm wasting your time.
<b>Thanks</b>

Answer 1

import java.awt.*;
import javax.swing.*;
public class SwingFrame extends JFrame{
   private JButton but;
   public SwingFrame(){
      Container c=getContentPane();
      c.setLayout(new FlowLayout(FlowLayout.LEFT, 5, 5));
      c.setBackground(Color.black);
      but = new JButton("Wyld Stallyns Rule!!!");
      but.setBackground(Color.green);
      c.add(but);
      this.setSize(200, 200);
      this.setDefaultCloseOperation( EXIT_ON_CLOSE );
   public static void main(String []args){
      new SwingFrame().show();
}