Thread: Help please.

I'm in an intro to Java course, and I'm trying to compile some code from my book - however I can't get it to compile.

I'm using JBuilder Person 9.0, and I've never had trouble before getting source to compile with it.

The error I'm getting is:

java.lang.Error: Do not use DrawArcs.add() use DrawArcs.getContentPane().add() instead
 
	at javax.swing.JFrame.createRootPaneException(JFrame.java:458)
 
	at javax.swing.JFrame.addImpl(JFrame.java:484)
 
	at java.awt.Container.add(Container.java:307)
 
	at DrawArcs.<init>(DrawArcs.java:8)
 
	at DrawArcs.main(DrawArcs.java:13)
 
Exception in thread "main"

And here is the source code:

import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.Graphics;
 
public class DrawArcs extends JFrame {
  public DrawArcs() {
    setTitle("DrawArcs");
    add(new ArcsPanel());
  }
 
  /** Main method */
  public static void main(String[] args) {
    DrawArcs frame = new DrawArcs();
    frame.setLocationRelativeTo(null); // Center the frame
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(250, 300);
    frame.setVisible(true);
  }
}
 
// The class for drawing arcs on a panel
class ArcsPanel extends JPanel {
  // Draw four blazes of a fan
  protected void paintComponent(Graphics g) {
    super.paintComponent(g);
 
    int xCenter = getWidth() / 2;
    int yCenter = getHeight() / 2;
    int radius = (int)(Math.min(getWidth(), getHeight()) * 0.4);
 
    int x = xCenter - radius;
    int y = yCenter - radius;
 
    g.fillArc(x, y, 2 * radius, 2 * radius, 0, 30);
    g.fillArc(x, y, 2 * radius, 2 * radius, 90, 30);
    g.fillArc(x, y, 2 * radius, 2 * radius, 180, 30);
    g.fillArc(x, y, 2 * radius, 2 * radius, 270, 30);
  }
}

Any help would be greatly appreciated, thanks.

Hi Bruzurk,
can u tell me what do u jdk's version use for compiling?
I'm using jdk1.6.0.18 and I don't have your problem.

Bye

Originally Posted by lucasantos

Hi Bruzurk,
can u tell me what do u jdk's version use for compiling?
I'm using jdk1.6.0.18 and I don't have your problem.

Bye

Hey, thanks for the reply. I got it to compile using the command prompt (javac DrawArcs.java), but when I try to run the class file it gives me an error, does it give you an error aswell?

I see a draw like a ventilator.
I don't have runtime error.

If you're using the command prompt for compiling, you can type
java -version
and you know your jdk's version.

Originally Posted by lucasantos

I see a draw like a ventilator.
I don't have runtime error.

If you're using the command prompt for compiling, you can type
java -version
and you know your jdk's version.

I believe I'm using the same version as you. My JDK folder name is: jdk1.6.0_18

I'm using Eclipse. Can u try with it?

Bruzurk,

I also ran your code using Eclipse and it compiled fine for me. The code itself looks fine.

I would strongly recommend downloading Eclipse for your Java development as it has great advantages including a very useful debugger and great error detection before runtime. This is a great tool to have especially if your going to take more Java classes. Its available at "www.eclipse.org/downloads" and its completely free.

Dejan

As tell you copeg, if DrawArcs constructor is

public DrawArcs() {
setTitle("DrawArcs");
getContentPane().add(new ArcsPanel());
}

u don't have problems

Re-installed the JDK, and started using Netbeans - it made everything work fine. Thanks for the help everyone.