I have created a WAR file by the following command:
jar -cvf myServlets.war DemoServlet.class CallServlet.html

The WAR file was successfuly created & I had deployed it on the Server.
But when I try to access the servlet through the html page, the server returns an error stating "Resource Not Available"
P.S. I had set the context-root & the application name properly.

Please suggest as to how can I rectify this problem?

What are you using for your server, and where in the server directory did you deploy the application? Is your html page in the same package as the servlet? Did you properly map the servlet path in the web.xml file?