servlet -> applet -- > Communication

[gurumoha]

I need a logic / idea for establishing communication from servlet to applet.
whenever the user login to server, session time will be allocated to the user, when the user logs on the server, server should initiate communication to the applet then server sends data to the applet along with userid and session time. as a response applet should able to generate the remainder notification for the user's session expiration for every 15 mins. here i need some logic or idea which can able to initiate communication from the servlet / webapp to the applet. your help is highly appreciated. thanks in Advance.