Java HotSpot Virtual Machine

Hi

Chapter 4 of the "Microsoft Java Virtual Machine Transition Guide for IT Professionals" [part of the documentation for "The Diagnostic Tool for the Microsoft Virtual Machine"] contains[under a discussion of disabling Java] :
(a) '... the Sun JRE, which "impersonates" the Microsoft Java Virtual Machine in IE ...';
(b) 'Some Java plug-ins install in a Windows system by "impersonating" the Microsoft Java Virtual Machine using the same registry entry and Class ID in installation ... Be cautious when installing JREs that impersonate the Microsoft Java Virtual Machine ...'.

Can anyone provide more information about this "impersonation" and what to be "cautious" about?
In particular:
(1) Does the impersonation only affect interpretation of applets under Internet Explorer plus any direct HTML references to the associated registry entries [and not any direct executable references to the Microsoft Java VM]?
(2) Does the Microsoft Java VM have to be retained [even if another JRE is installed] to support any direct executable references to it?
When I run "The Diagnostic Tool for the Microsoft Virtual Machine" on a Windows 98SE system, its VM Dependency Report has many entries for Micrsoft library modules - eg IEDETECT.DLL - and its Visual J++ Class Report has many entries - eg C:\WINDOWS\SYSTEM\MSHTML.DLL.
There is no information about whether such dependencies are critical - the modules may have alternative paths if the MSJVM is not installed.
At this stage, I suspect that Microsoft is not going to issue updates to such modules [Windows 98 is no longer fully supported] and therefore it would be unsafe to remove the Microsoft Java VM.

Chapter 4 also mentions a "TreatAs" subkey, and recommends removing it. Does the Sun JRE install or rely on such a subkey?

Chapter 6 says that "The use of Microsoft extensions is easy to find in current J++ source files ..." but is there any way that users without access to such source files can find which executable modules are dependendent on the entries shown when I run "The Diagnostic Tool for the Microsoft Virtual Machine" and look at its Visual J++ JAVAREG Report [which lists CLSIDs and associated Java classes for msjava.dll].

Regards,
Peter Jones