Patch Set 2: Looks good to me, but someone else must approve

As a general observation, it's useful to decouple the text of the message to the variable name - this renaming technically is an API breakage because this is in a public class (I think ... the package doesn't have 'internal') whereas you can always change the text in the properties file. Since we're in incubation, it doesn't matter - but either way, it probably makes sense for this class to be in an internal package rather than part of the API, if it's a public package (which it looks like it is).