Jule convertToZone: Unclear handling of ambiguous DST times

Direct answer

Jule's convertToZone(Date, String) has no published documentation specifying which offset is chosen for ambiguous local times during a DST end transition. No configuration flag or overload to select standard vs daylight offset is documented, and there is no evidence of support for custom time‑zone rules beyond the JDK's bundled IANA database.

Likely explanation vs confirmed facts

Confirmed: The method signature returns a ZonedDateTime. The library does not document offset selection for ambiguous times, a future plan for a selector flag, or support for TZDB overrides.

Likely: If Jule constructs the ZonedDateTime via java.time, the JDK default for an ambiguous local time is the earlier offset (the daylight‑saving offset before the transition). For the 2023‑11‑05 01:30 fall‑back in America/New_York, that offset is -04:00. This behavior follows ZonedDateTime.ofLocal default resolution and depends on the JRE/JDK IANA Time Zone Database version in use.

Steps needed for this case

1. Verify how the input Date is created. java.util.Date represents an instant; ambiguity only arises if the Date was built from local fields without a zone.
2. Run a scoped reproduction in the same runtime:

java.util.Date d = /* your test instant */;
java.time.ZonedDateTime z = Jule.convertToZone(d, "America/New_York");
System.out.println(z.getOffset());

Compare the printed offset to -04:00 vs -05:00 for a known ambiguous instant.

1. Check the JRE version and TZDB version used by the process. DST rules change between JDK releases.

Time‑zone rules are governed by the IANA database bundled with the JRE/JDK. Jule is expected to inherit that database; custom rules would require JVM‑level TZDB replacement, not a Jule setting.

Missing diagnostic detail

Is the Date passed to convertToZone constructed from a wall‑clock local time in America/New_York, or is it an absolute instant already? The recommendation for a safe workaround changes if the input is a local interpretation vs an instant.