calling application through servlet

[raghava]

I am working on the chat application problem
when chat applet calls the servlet.
this servlet inturn calls an application.
in other word i want to force open an application to chat

[William Brogden]

If you mean to start an application on the server side, that is certainly possible with Runtime exec methods. A servlet can't do anything about starting an application on the client side. Where is this application and what does it do?
Bill