Ah BTW, there is a TimeZone.getTimezone(ZoneOffset.UTC) construct which can be 
used. The ZoneId is also immutable, but that construct does say nothing about 
TimeZone instance.

Gruss
Bernd
--
http://bernd.eckenfels.net

________________________________
Von: Bernd Eckenfels <e...@zusammenkunft.net>
Gesendet: Samstag, September 1, 2018 3:22 AM
An: core-libs-dev@openjdk.java.net
Betreff: Are TimeZone instances guaranteed to be thread-safe

Hello,

I am not sure I missed it, but it looks like there is no definition in the JCL 
JavaDoc about instances of j.u.TimeZone (specifically SimpleTimeZone as well as 
instances obtained with getDefault or by Id) beeing reentrant/thread Safe or 
not. (There are for examplequite a few non-final fields in SimpleTimeZone as 
well),

Since TimeZone is used together with Calendar it might be natural for 
developers to know.

Is there a helper/factory which would allow access to some standard timezones 
(at least GMT/UTC). This might be especially useful if we cannot define 
TimeZone instances generally as thread safe, because then we can at least 
declare it for this „fast“ implementation.

[ Background of my question is BTW the rs.getTimestamp(idx, Calendar) method in 
the JDBC API where the need for constructing a Calendar object is painful and 
it would help if I could at least use new Calendar(SimpleTimeZone.UTC). (And 
having an alternative like getTimestamp(Int, ZoneId) would be even better ]

I can imagine naming it GMT vs. UTC might also be a nice bike shed.

Gruss
Bernd
--
http://bernd.eckenfels.net

Reply via email to