I'm prepping a Google Data + App Engine article right now which uses the Java runtime. This is what I have regarding dependencies, specifically for the Documents List service:
To use the Google Data client library (
http://code.google.com/p/gdata-java-client/) in your App Engine application, you must first copy the JARs listed below from the lib directory of the gdata-java-client package to your app's war/WEB-INF/lib directory:
gdata-client-1.0.jar
gdata-client-meta-1.0.jar
gdata-core-1.0.jar
gdata-docs-3.0.jar
gdata-docs-meta-3.0.jar
gdata-media-1.0.jar
google-collect-1.0-rc1.jar (from gdata/java/deps)
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If you are not using the Google Documents List API, you will have to replace gdata-docs-3.0.jar and gdata-docs-meta-3.0.jar with the JARs for the service you're trying to use. Also, be sure you're following this FAQ:
I hope this helps.
- Jason