1)How do we deal property file in servlets ? http://wiki.apache.org/tomcat/HowTo#head-45c3314139cb900ddd43dde2ff671532e6e844bc
2)what methods do we use in servlet-applet communication ? doPost and doGet
3)what is http tunneling.. The act of communicating through a firewall by streaming all of the data through ports open for HTTP communication. (look up "SOAP", and "Web Services").
4)what is servlet chaining An outdated technique for setting up a pipeline of servlets which pass context from one to another. This has been replaced with filters and requestDispatchers. The Servlet Spec describes each in detail (link in my signature).