A java.util.ResourceBundle replacement for configuration properties. Helpful for metadata to properties for the purpose of validating, inspecting, binding, etc. properties without infringing on any existing useage of those resources.

For example the property:
warning.dialog.alert.icon=/images/w_alert.png

Could be analyzed by acceptance tests or validation code:
#@ location:warning_dialog; resource_type:png-image
warning.dialog.alert.icon=/images/w_alert.png

Now at runtime, the annotated keys and values are available via the AnnotatedResourceBundle class. Keeping with the same example:

AnnotatedResourceBundle annotatedResourceBundle = new AnnotatedResourceBundle(
    "images.properties", getClass().getClassLoader());
for(Entry<String, String> entry : annotatedResourceBundle.getAttributes("warning.dialog.alert.icon").entrySet()){
    System.out.println(entry);
}

would output:
location=warning_dialog
resource_type=png-image