Bug#6806723 issue still exist in 7u40.

    The Java authentication login box does not accept a backslash in the user name. If you enter:

     domaine\username

     then the web server receive only the username without domaine. With a slash it is working. But the correct writing on windows is with a backslash. The user also does not see it. Only the login is failing. I have test it with basic authentication and Java 1.6.0_11.

      The client code to show the dialog box:
             new URL("http://localhost/xyz/securepage.asp").openConnection().getInputStream();

Attached a test program. This test start a micro webserver in the applet with basic authentication.

   > copy it in any web server
   > reduce the security of your Java VM
   > call the html page in the browser
   > press the button in the applet
   > enter any login name with domain name and backslash
   > see in the console what the server received

check screenshot bigjdajj.png for error message