Note:  This has been updated for 2013 at https://segal.org/java/SigningTestApple/ but the original version at the time of the bug report is below:

Steps to reproduce:

1.  Using Safari, go to a signed applet such as the one on this page (www.segal.org/java/FocusTextField/).  One can't type into the TextField, regardless of whether one chooses Allow or Deny in the digital certificate dialog box.

2.  Clicking next to a similar non-signed applet such as the one at www.segal.org/java/FocusTextField/nonsigned.html one can't type into the TextField there either.  However, that non-signed version of applet works if you go to it right after opening the browser, before going to the signed version.

Workarounds:

• Checking "Allow all applets from "www.segal.org" access" in the digital certificate dialog box, closing the browser and re-opening it results in the TextField working on all subsequent trials.
• Firefox 3.5.5 on the Macintosh does not have this problem

Additional information:

• Tested on Safari 4.0.4 on Mac OS 10.6.2 with java.version 1.6.0_15
• The problem appears related to domain-based security changes made by Apple in June 2009, as detailed at http://blogs.sun.com/javafx/entry/new_security_warning_for_mac.  On Mac OS X 10.6 it is possible to clear the domain-based security permission using the "Security" tab in /Applications/Utilities/Java Preferences.app.
• This works fine on Firefox or Internet Explorer on Windows.  Safari on Windows has not been tested yet.

If you have any insights or comments about this page please contact Mickey Segal.  A listing of  many Java resources is at this link.

Source code:

import java.awt.*;
import java.applet.*;

public class SigningTestApple extends Applet {

public void init()
{
  setBackground(new Color(255, 240, 200));
  TextField textField = new TextField(20);
  add(textField);
  textField.requestFocus();
}

public void paint(Graphics g)
{
  try
  {
   String userHome = System.getProperty("user.home");
   g.drawString("Signing worked. The user.home property is: " + userHome, 10, 70);
  }
  catch (SecurityException e)
  {
   g.drawString("Signing didn't work. The SecurityException is: " + e.getMessage(), 10, 70);
  }
}
} // END OF Class SigningTestApple