The application contains Java 7 classes, but the --use_java7 flag has not been set.
so hard to understand?
You are working with Java7 on your development machine. There are certain differences between Java6 and Java 7 ( New Features in Java7
so to use your full-blown, serious rocking Java7 toxicated application, you need to tell the Google App Engine that your code is working on Java7, and that the Google App Engine should be aware of that.
Blogpost about using Java7
] @ Google App Engine Blog
What I would do:
- uninstall Java7 on th develoment machine
- install java6 latest Release
- configure to use Java6
- try again if App runs (all functions!).
100 times safer.