I think what you actually want is a server context (stored on the server). Or - as it's more commonly known - a "Session". The Java applet sandbox discourages the mechanisms that would allow client-side applet-to-applet collusion.
An IDE is no substitute for an Intelligent Developer.
What are you doing? You are supposed to be reading this tiny ad!
the new thread boost feature brings a LOT of attention to your favorite threads