I don't think there is anything in the spec for doing this.
Check with the documentation for the container you're using to see what they offer. I know that
Tomcat will show you the deployed servlets if you fire up the HTML Manager app and go to
Server Status ->
Complete Server Status you'll see a list of all the servlets deployed in each application along with some data for each of them.
Mind if I ask why you would want to know this?
