ant jdktzCheck reports two failures in TimeZoneFormatTest
This is probably related to negative daylight saving time. Checks if JDK already support this - and in this case, find out how to handle it in ICU.
Oracle JDK now supports negative DST offset for Dublin, while ICU/CLDR still do not. As the result, following code snippet
prints out: Thursday, February 1, 2018 at 12:00:00 AM Irish Standard Time
Note: JDK TimeZone for Dublin returns isDST = true on Jan 1, 2018. ICU time zone format look up a DST name for Dublin, and returns "Irish Standard Time" instead of "Greenwich Mean Time".
If I comment out the first line (TimeZone.setDefaultTimeZoneType(TimeZone.TIMEZONE_JDK), then correct format is returned: "Thursday, February 1, 2018 at 12:00:00 AM Greenwich Mean Time"