Did you place the compiled class file under classes according to the package name?
Note that the server must be restarted after changes to web.xml and class files.
Double-check that Tomcat is recognizing "First" as holding a web application by placing a plain index.html file there. If you can't open http://localhost:7777/First/index.html then there is probably something wrong with your directory structure.
I’ve looked at a lot of different solutions, and in my humble opinion Aspose is the way to go. Here’s the link: http://aspose.com