Re: JDK-8074023: Clock.system(ZoneId) could be optimized to always return the same clock for a given zone

[Peter Levart]

On 04/23/2015 10:33 PM, Roger Riggs wrote:

Hi Peter,

The defaultTimeZone is cached in java.util.TimeZone the first time it is referenced

and is not updated after that.  See java.util.TimeZone.getDefaultRef().

Regards, Roger

But any code (with enough privilege) can update it:

abstract public class TimeZone .... {

    public static void setDefault(TimeZone zone)
    {
        SecurityManager sm = System.getSecurityManager();
        if (sm != null) {
            sm.checkPermission(new PropertyPermission
                               ("user.timezone", "write"));
        }
        defaultTimeZone = zone;
    }



Peter

On 4/23/2015 4:11 PM, Peter Levart wrote:

On 04/23/2015 09:53 PM, nadeesh tv wrote:

Hi all,

Please review this minor change which optimized Clock.systemDefaultZone() and Clock.system(ZoneId) to avoid creating new instance of Clock.SystemClock every time they are called.

Bug ID :  https://bugs.openjdk.java.net/browse/JDK-8074023

Webrev : http://cr.openjdk.java.net/~rriggs/nadeesh-tv-8074023/

Hi Nadeesh,

What happens if ZondeId.systemDefault() changes (TimeZone.setDefault()) *after* Clock class has already been initialized?

Regards, Peter