Thread: What did I do wrong here?

Well I'm starting to study a bit on Swing and the JFrame, so please, if this looks ugly please cut me a bit of slack >.<
This is what I've got:

package Core.Engine;
 
import javax.swing.*;
import java.awt.*;
 
 
 
@SuppressWarnings("serial")
public class Engine extends JFrame {
 
 
 
static int i;
	static JPanel PRIME;
	public Engine(){
 
		JButton[] BUTTON = new JButton[9];
		PRIME = new JPanel(new GridLayout(5,6));
		String b[] = {"1", "2","4", "3", "5",
					"6", "7", "8", "9", "0"};
 
		for(i = 0; i < BUTTON.length; i++){
			BUTTON[i] = new JButton(b[i]);
			BUTTON[i].setSize(30,30);
			};
 
		PRIME.add(BUTTON[i]);
	}
	public static void main(String args[]){
		Engine frame = new Engine();
		frame.add(PRIME);
		frame.pack();
		frame.setVisible(true);
	}
}

I get an ArrayIndexOutOfBoundsException on line 27 and 30 which would be in the Main argument...
Here's the exact error:

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 9
	at Core.Engine.Engine.<init>(Engine.java:27)
	at Core.Engine.Engine.main(Engine.java:30)

Could anyone tell me where I went wrong? The array has 9 elements. I set 9 chars... How did it go out of bounds?



Foot Note:
If you have any ideas on how I could improve this code please don't be afraid to mention it!