Need to find JRE Version for Sun Plugin

[John]

I am writing a java program that might be running in any JRE at the
command prompt.

Is there a way to determine programmatically what the computer user
has selected for his default JRE in his browser through the Sun plugin
without using an applet? For example an API that exposes the plugin
and allows me to determine the properties the user has set (default
JRE, what browsers he has installed, etc)

I understand that you can use System.GetProperty() to determine the
CURRENT version of the JRE that the program is running in. However
this could possibly be different from the JRE he has selected to run
in his browser. For example, he could be using a 1.2 JRE at the
command prompt, but a 1.4 JRE in Internet Explorer through the Sun
plug-in.

Any ideas?