Below is my web-xml.xml file
Is that a typo? Did you mean web.xml?
What URL are you using in the browser when you get the 404? It's hard to say why you are getting a 404 if we don't know the URL you were using.
Do you actually have a class named add_cardio_patient? That is not a typical
Java class naming convention.
It might also be helpful if you posted the contents of the deployed WAR file. You can get that by running "jar -tf xxx.war" where xxx.war is your war file name (including the path).