The Oracle java7 and older return Mrz as german march short name.
The Oracle java8 seems to have switched to the official (see http://de.wikipedia.org/wiki/Vorlage:Monat_Name-Nummer ) three letter short name Mär.
Some googling showed that IBM java has used the offical short name at least since 2008.
I propose as a fix that the non-english test language is changed to something other than Locale.GERMAN in DatePickerTest method myTestExecution. For example Locale.ITALIAN, which has had consistent localization in Java world. Plus of course the reference data in DatesPage1_ExpectedResult.html needs to be regenerated.