JRE dynamic Versioning

I understand that with dynamic versioning, if client machine does not have the "required version" (I don't know how to specify that), then the user should be prompted to download a version as specified by codebase attribute of the <Object> tag:


<OBJECT
classid="clsid:8AD9C840-044E-11D1-B3E9-00805F499D93"
codebase="somedir/jinstall-1_4_1_01-windows-i586.cab#Version=1,4,1,0,1" id=Java_Plug-in_1_4_1_011
>

... bunch of stuff ...

</OBJECT>

QUESTION 1:
Do we use the same classid for all JRE versions? If not, WHERE do I get it from? From [REF-1], it seems that we use the same classid for all JRE versions if we're using "dynamic versioning". Is this true?


QUESTION 2:
I've specified the following classid to indicate dynamic versioning:

CLASSID="clsid:08B0E5C0-4FCB-11CF-AAA5-00401C608500"

Then I installed the old JRE 1.4.1 onto my system. I tested my versioning support and pointed my browser to the page in which the applet is embedded using <OBJECT> tag (with dynamic versioning)

The applet didn't get loaded - "Loading applet..." message - but the user was not prompted to download the JRE

Reference:
1. http://www.bambookit.com/reference/j...bject_tag.html
2.
http://java.sun.com/products/plugin/versions.html