Could not find or load main class cmd

Question

I compiled some sample code with javac and when i tried running it here's what i get:

C:\Users\Lenis>cd C:\Java\2D

C:\Java\2D>java donut.board
Error: Could not find or load main class donut.board

I tried writing "java -cp . donut.board" and still get the same.

My classpath is : "C:\Program Files\Java\jdk1.7.0_02\lib\tools.jar;."

How to fix it?

And here is the code:

package donut;

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.geom.AffineTransform;
import java.awt.geom.Ellipse2D;
import javax.swing.JPanel;

public class Board extends JPanel{

public void paint(Graphics g)
{
  super.paint(g);

  Graphics2D g2 = (Graphics2D) g;

  RenderingHints rh =
        new RenderingHints(RenderingHints.KEY_ANTIALIASING,
                           RenderingHints.VALUE_ANTIALIAS_ON);

  rh.put(RenderingHints.KEY_RENDERING,
         RenderingHints.VALUE_RENDER_QUALITY);

  g2.setRenderingHints(rh);

  Dimension size = getSize();
  double w = size.getWidth();
  double h = size.getHeight();

  Ellipse2D e = new Ellipse2D.Double(0, 0, 80, 130);
  g2.setStroke(new BasicStroke(1));
  g2.setColor(Color.gray);


  for (double deg = 0; deg < 360; deg += 5) {
      AffineTransform at =
          AffineTransform.getTranslateInstance(w / 2, h / 2);
      at.rotate(Math.toRadians(deg));
      g2.draw(at.createTransformedShape(e));
    }
}
}

score 3 · Answer 1 · answered Feb 08 '12 at 10:34

3

You don't have main method in the class and also when invoking you have to give donut.Board (capital B) It is case sensitive. Add the main method.

answered Feb 08 '12 at 10:34

prajeesh kumar

1,916
1
17
17

score 1 · Answer 2 · answered Feb 08 '12 at 10:37

1

Your class name Board starts with capital.

answered Feb 08 '12 at 10:37

Kuldeep Jain

8,409
8
48
73

score 0 · Answer 3 · edited Mar 11 '15 at 20:26

Include your main method in your Board class, you can see a simple example here: http://docs.oracle.com/javase/tutorial/java/concepts/class.html

Also change java -cp . donut.board to java -cp . donut.Board

As you can see in the following code, this is a class that by itself can´t do anything, this is saying just what you can do with a Bicycle but you are not using all that behavior

 class Bicycle {
    int cadence = 0;
    int speed = 0;
    void changeCadence(int newValue) {
         cadence = newValue;
    }
    void speedUp(int increment) {
         speed = speed + increment;   
    }
    void applyBrakes(int decrement) {
         speed = speed - decrement;
    }
    void printStates() {
         System.out.println("cadence:" +
             cadence + " speed:" + 
             speed );
    }
}

So if you want to use this class you can create another class where you include the main method, now you are really using all the behavior that you gave to a Bicycle in the previous class

class BicycleDemo {
    public static void main(String[] args) {
       Bicycle bike1 = new Bicycle();
        Bicycle bike2 = new Bicycle();

        bike1.changeCadence(50);
        bike1.speedUp(10);
        bike1.printStates();

        bike2.changeCadence(50);
        bike2.speedUp(10);
        bike2.changeCadence(40);
        bike2.speedUp(10);
        bike2.printStates();
    }
}

While this link may answer the question, it is better to include the essential parts of the answer here and provide the link for reference. Link-only answers can become invalid if the linked page changes. — Rick, Mar 11 '15 at 17:32
@Rick thanks for your comment, I'll add some code to improve the answer :) — salembo, Mar 11 '15 at 18:50

Could not find or load main class cmd

3 Answers3