java cache

[Matthijs Blaas]

I found that when an applet is cached (using Sun jvm), it's placed in the
Sun\Java\Deployment\cache\javapi\jar\ folder. The files are saved with
somekind of checksum added to them (fx: file1.jar-md5checksum?.zip). Does
this prevent hackers from modifying the applet and have the website execute
a modified applet instead of the original one? If so, is this security
mechanism provided with every jvm? (ie MS, IBM etc?)

Does anyone know some more about this?

Thanks in advance!

-Thijs