Summary

Remove JDK1.1 compatible behavior for "EST", "MST", and "HST" time zones.

Problem

In JDK1.1, TimeZone class had time zones "EST", "MST", and "HST" as links to "America/New_York", "America/Denver", and "Pacific/Honolulu" time zones which have since been deprecated (https://docs.oracle.com/en/java/javase/23/docs/api/java.base/java/util/TimeZone.html#three-letter-time-zone-ids-heading). Then in JDK8, with the introduction of java.time package, these three time zones are switched to fixed offset time zones, "-05:00", "-07:00", and "-10:00" respectively. The implementation also allowed to flip the mappings to JDK1.1 compatible one, with the non-public system property sun.timezone.ids.oldmapping set to true/yes. However, the latest TZDB (2024b) changed the definitions of those time zones to links to "America/Panama", "America/Phoenix", and "Pacific/Honolulu" respectively, which was discussed in the CSR JDK-8340138. Thus the JDK1.1 compatible switch is now moot, and should be removed. Keeping dual behavior for those time zones makes the code complex.

Solution

Remove the internal system property sun.timezone.ids.oldmapping and related code/tests. Those three time zones remain intact, only removing the compatibility switching capability.

Specification

N/A. Behavior change only.