Java.policy codebase ignored

Question

I've recently been trying to allow an applet on a local webpage to write to a file in the same folder. I've been using the following .java.policy file:
grant codeBase "file:${user.home}/My Documents/folder/*" {
  permission java.io.FilePermission "${user.home}${/}My Documents${/}folder${/}*", "read,write";
};The HTML is in the folder called "folder" as above. So is the JAR file for the applet. In the HTML is:
<applet code="foo.class" archive="foo.jar"></applet>The applet implements a "load" function and a "save" function, which are called like:
data=document.applets[0].load(filename);
document.applets[0].save(filename,data);Everything works perfectly using Opera, but fails in IE and Firefox unless I remove the codebase from the grant, leaving just a universal "grant {".
I'm using 1.5.0_06. I've tried other codeBase values such as "file:C:/-", "file:///C:/-", "file:C:/Documents%20and%20Settings/-", and similar variations (too many to list). I've also tried adding a codebase attribute to the applet tag with the value "file:///C:/Documents%20and%20Settings/username/My%20Documents/folder/" (value derived from document.location).
Is there some way to limit granting of permissions to applets in a particular folder that works in all browsers? I know Opera bypasses the Java plugin to access the runtime directly, hence my feeling this is a plugin bug.
Thanks in advance for any help.

Answer 1

Use doprivileged for signed code called by javascript
Signing applets:
http://forum.java.sun.com/thread.jsp?forum=63&thread=524815
second post and last post for the java class file using doprivileged
Still problems?
A Full trace might help us out:
http://forum.java.sun.com/thread.jspa?threadID=656028