Whats the problem calling a servlet from a java application, even if its not exposed as a web service. Look into URLConnection or HttpURLConnection classes under java.net package. Ankita is facing a different issue i.e. hitting the servlet from oracle.
That would be an strange idea, which I've never considered before, but I think it worth your effort to get it through.
Connect to a Servlet, I just wonder what you are doing by then. Do you mean that you would like to request some message from it just like an browser do, or something like web service?