To be verified with unit tests:

• items returned by JcrAssetProvider should return a path that's relative to its rootPath (i.e if rootPath==/foo, then Asset.getPath()==/bar for an asset physically stored in /foo/bar in jcr.
• get*ByPath should take paths relative to the rootPath (PathAwareAssetProvider.getAsset(/bar) should return the asset physically stored in /foo/bar in jcr.
• Ideally, the provider should be isolated, such that a call to getAsset(someId) would fail if it points to an asset stored outside /foo.