A value, in milliseconds, indicating the interval of how much earlier the warning that the session is about to expire is to be issued. For details on how to setup a callback that will be invoked on before session expiry see ice.onBeforeSessionExpiry API.
<context-param>
<param-name>org.icefaces.warnBeforeSessionExpiryInterval</param-name>
<param-value>15000</param-value>
</context-param>