In the training we use the helloworld app as described in the documentation:
http://documentation.magnolia-cms.com/display/DOCS/Programming+an+app#Programminganapp-HelloWorldexample

The code worked without problems in various trainings. Last training 2 participants used JDK7 instead of JDK6 in Eclipse. Both running on Windows 7.
Both hat the same problem:
The view of the greeter subapp was not injected into the presenter via IOC, see stacktrace in file 'stacktrace-helloworld.txt'. The git repo 'training-apps-ux-module.zip' is the repository the participants was using within eclipse. The original code base is located in:
https://git.magnolia-cms.com/gitweb/?p=training/training-apps-ux-project.git;a=tree;f=training-apps-ux-module;hb=HEAD
The code base the people use are in all cases the same. All register in the same way the Views in the module descriptor.

I assume that the compiling with JDK7 is the source of the problem, as they used the JDK7 for runtime all week before. Any Magnolia App requests the View in the presenter by IOC, but only when they used their first IDE compiled app it didn't work anymore.

The problem is triggered:
The main subapp opens and displays normal.
When clicking on the "Greeter" Button which calls the greeter subapp via a "gotoLocation()" call the error appears. The greeter subapp never opens.