Eclipse + Google AppEngine + Vaadin

[Rich7 (Rich Ryan)]

Thanks so much I followed your directions but get a different result in some areas and in the end I still end up with the save exception.

I am using Vaadin 7.0.2, App Engine SDK 1.7.5, and JDK1.6.0_37 using Eclipse Juno (with all updates applied). I see the same issue on two different computers running a similar software stack, but one is Windows XP 32-bit and the other is Windows 8 64-bit.

@mcm _

sorry, no clue on your UIProvider problem… could it be that you have created a plain Vaadin Application instead of GAE ?

anyhow, this guidance works for me, and i was able to reproduce it mutiple times.

1. create a vaadin 7 project
   in eclipse:
   • File > New > Other
   • select “Vaadin 7 Project” > Next
   • enter Project Name
   ∘ Target runtime => leave it empty
   ∘ Configuration => Vaadin 7, Java 6, Servlet 2.4 ( since GAE still doesn’t support servlet 3.0, and Java7 is experimental)
   ∘ Deployment configuration => Google App Engine servlet
   ∘ > Next > Next > Next > Finish

2. Add the following line to war/WEB-INF/appengine-web.xml
   • assure that ‘session-enabled’ is active true
   • add ‘threasafe’ true

3. fix Project Built-Path
   • right click the project and select Properties
   ∘ select Google > App Engine
   ‣ check “Use Google App Engine”
   ‣ enter “Application ID”
   ‣ enter “Version”
   ‣ select “Datanucleus JDO/JPA version” => v2
   ‣ OK (close the Properties window)
   • right click the project and select Properties
   ∘ select Java Built Path => Libraries
   ‣ select the double entry of “App Engine SDK” > Remove

I only have one App Engine SDK entry.

‣ select "ivy.xml [default]
" > Edit…
• select Classpath tab
∘ check “Enable project specific settings”
∘ check “retrieved artifacts”
∘ Retrieve pattern => "war/WEB-INF/lib/[artifact]
-[revision]
.[ext]
" (without the quotes)
∘ Types => jar
∘ Finish (close Edit Library window)
∘ select Java Built Path > Order and Export tab
‣ set the order accordingly
• ${project_name}/src
• ivy.xml [widgetset-compile]

• JRE System Library
• EAR Libraries
• App Engine SDK => this must be above Web App Libraries
• Web App Libraries
• ivy.xml [default]
=> this must be checked

4. remove strange errors in eclipse
   • open the “Problems” view in eclipse > select Errors > right click on it > Delete
   • to clean up the project, select from the menu Project > Clean…
   ∘ select “Clean projects selected below” > select the Vaadin+GAE project > OK
   this removes all errors from the view and cleans the project, so the project can re-compile it-self. otherwise eclipse will keep asking if you’re sure that you want to debug/run/deploy even with errors

I can delete the errors, but as soon as I do Project->Clean and rebuild the errors reappear. But they don’t prevent me from starting the app.

5. debug/run the application
   right click the project > Debug As > Web Application
   in case any single of the steps should be missing you will receive an error and it won’t work…

6. smoke test (deploy to GAE)
   right click the project > Google > Deploy to App Engine…

The project launches locally and appears correct until I do anything that would send info to the server (for example as soon as I click the button in the default template app).

I am stumped about the cause of the problem. Is your environment different?