[PATCH] Support for UTC Zones with TimeZone.getTimeZone()

Naoto Sato naoto.sato at oracle.com
Wed Dec 20 18:19:04 UTC 2017

Hi Naufal,

Thank you for the patch. It does seem to be a bug. However, TimeZone 
class defines CustomID as "GMT+(offset)", so I'd rather fix it in 
GregorianCalendar.from() to recognize those "UTC+offset" zones.


On 12/16/17 2:27 AM, Mohamed Naufal wrote:
> Hi,
> I noticed that with the following data:
> LocalDateTime ldt = LocalDateTime.parse("2017-01-01T00:00:00");
> ZonedDateTime dt1 = ZonedDateTime.of(ldt, ZoneId.of("GMT+10"));
> ZonedDateTime dt2 = ZonedDateTime.of(ldt, ZoneId.of("UTC+10"));
> dt1.equals(dt2) returns true as expected, but with:
> GregorianCalendar gc1 = GregorianCalendar.from(dt1);
> GregorianCalendar gc2 = GregorianCalendar.from(dt2);
> gc1.equals(gc2) returns false.
> Looking at the code, I see when a GregorianCalendar is being constructed,
> TimeZone.getTimeZone() gets called, but it doesn't recognise UTC time-zones
> with offsets, and falls back to GMT(+0), whereas ZoneId treats GMT and UTC
> based zones equivalently.
> PFA a patch to fix this.
> Thank you,
> Naufal

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