Applets hang when using plugin 1.5 in Linux with Mozilla 1.7.x

FULL PRODUCT VERSION :
java version "1.5.0_01"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_01-b08)
Java HotSpot(TM) Client VM (build 1.5.0_01-b08, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Red hat Linux - 2.4.20_6

EXTRA RELEVANT SYSTEM CONFIGURATION :
Client - Mozilla 1.7.3
https Webserver - with authentication turned on

A DESCRIPTION OF THE PROBLEM :
   From the applet when we try to make a URL connection and geinputstream
the browser hangs. We have authentication turned on the webserver. I think
the plugin is trying to popup the login dialog and some how it can't do
that and hangs there.
This works okay with jre1.5 on windows
On Linux it works with jre1.4.2 but not 1.5

Here is the code

String str = "https://ppp.qqq.com/admin/test.gif";
     try {

       System.out.println("Getting ->" +str);
       URL url = new URL(str);

       URLConnection con = url.openConnection();

       if(con.getAllowUserInteraction())
         System.out.println("User interaction allowed");
       else
         System.out.println("User interaction not allowed");

       con.setDoInput(true);
       InputStream _inp = con.getInputStream(); //Hangs here



Tried using httpsurlconnection that also didn't help.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Use the above code from an applet and connect to a webserver with
authentication turned on

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The applet should fetch the file.
ACTUAL -
Browser hangs

ERROR MESSAGES/STACK TRACES THAT OCCUR :
No error messages on the java console or even in the trace file

REPRODUCIBILITY :
This bug can be reproduced always.
###@###.### 2005-2-08 11:12:59 GMT