I started using appfog ( http://www.appfog.com/ ) and I haven't found any resources explaining how to deploy a simple Java Web application. I tried extracting a .war file I have and then updating the app but I got no luck.
Cheers
Deploying Java Web Application on AppFog is pretty easy once you see an example. Here is some documentation: https://docs.appfog.com/languages/java
Step 1) Build a war file and cd into the directory with the war file in it (usually cd target)
Step 2) af push
You do not want to extract the war file, you just need to be in the same directory as the war file.
Hope this helps! Best of luck! There is a great and vibrant community of AppFog Java users in the google group as well: https://groups.google.com/forum/#!forum/appfog-users