Currently, modules do things like

String magnoliaHome = MagnoliaConfigurationProperties.getProperty("magnolia.home");
configSourceFactory.yaml().from(Paths.get(magnoliaHome))

If magnolia.home is not defined, this throws the ugly exception below. There are several things we could do:

• pass a String of the path to configSourceFactory instead of a Path instance.
• pass the name of the property, and let configSourceFactory call MagnoliaConfigurationProperties
• add method to MagnoliaConfigurationProperties to get a Path instance from a property name (can check for existence and it being a directory)
• add getMagnoliaHome() to MagnoliaInitPaths and make this property a first class citizen. This could also ensure that even if the property isn't defined, we fallback to app-root-dir (rather than relying on the fact that the property exists with its default value, which is indeed ${magnolia.app.rootdir}
  I would tend to favor #4, but there are perhaps more ideas (and/or combinations thereof). Let's update the title of this issue once we decide.

[INFO] [talledLocalContainer] 2015-03-04 11:18:22,784 ERROR info.magnolia.module.ModuleManagerImpl            : Can't start module ui-framework
[INFO] [talledLocalContainer] java.lang.NullPointerException
[INFO] [talledLocalContainer] 	at sun.nio.fs.UnixPath.normalizeAndCheck(UnixPath.java:77)
[INFO] [talledLocalContainer] 	at sun.nio.fs.UnixPath.<init>(UnixPath.java:71)
[INFO] [talledLocalContainer] 	at sun.nio.fs.UnixFileSystem.getPath(UnixFileSystem.java:281)
[INFO] [talledLocalContainer] 	at java.nio.file.Paths.get(Paths.java:84)
[INFO] [talledLocalContainer] 	at info.magnolia.ui.framework.UiFrameworkModule.start(UiFrameworkModule.java:84)