That said, I have never done any customer work targeting the AppEngine platform because no one has requested it. (Although I have enthusiastically used AppEngine for some of my own projects and I have written several AppEngine and Wave specific articles.) I still host KnowledgeBooks.com on AppEngine.
I wrote a GWT + AppEngine app for my own use about a year ago, and since I always have at least one EC2 instance running for my own experiments and development work I decided to move my app. It turns out that converting my app is fairly easy using these steps:
- Copy my IntelliJ project, renaming it and removing AppEngine facets and libraires.
- Add the MongoDB Java required JARs
- I had all of my Objectify datastore operations in a single utility class on the server side - I converted this to use MongoDB