- I pushed a Python starter app to GAE, and I confirmed that it worked. Then I pushed a Java starter app to the same GAE application. I was getting the "Gwt module 'modulenamehere' may need to be (re)compiled" error.
- It turns out that when you push an application, it does not replace the old application; it simply pushes the new files, with overwrites where the names are the same and adds where the names are unique.
- When you push V2, it pushes all files to V2, but it leaves V1, and V1 remains as the application that is run when you enter http://appnamehere.appspot.com.
- You either have to go to the GAE Dashboard and make V2 the default, or enter http://2.latest.appnamehere.appspot.com. (That's a prefix of version number, plus "latest".)