(keitai-l) i-appli jar files hackable?

just wondering if it's possible for someone using a normal pc-based web 
browser to access a site with an i-appli link and somehow download the 
i-appli's jar file (by re-enterring the .jar file's url), retrieve the .jar 
from the browser's cache directory, open the jar, reverse engineer 
the .class files to expose the source code?

just wondering what security measures there are, besides doing an initial 
USER_AGENT check and denying access to all non-i-appli clients?  is the 
latter sufficient?

thanks.

--------------
help the survivors of international disasters today: http://www.redcross.org/ 


[ Did you check the archives?   http://www.appelsiini.net/keitai-l/ ]