RFR: 8266846: Add java.time.InstantSource [v3]

[Daniel Fuchs]

On Wed, 19 May 2021 08:41:08 GMT, Peter Levart <plevart at openjdk.org> wrote:

>> This isn't my logic - it is existing code that has been moved. I'm not a fan of infinite retry loops as the can hang the system. But I'm happy to change it to work that way if there is a consensus to do so.
>
> I see the localOffset passed to VM.getNanoTimeAdjustment() has to be in the range of current time +/- 2^32 seconds. This means the thread would have to sleep for ~136 years before the exception is triggered. I think this is more than enough. :-)

Exactly. You could hit the 1ns if the operating system clock was concurrently moved backward by a NTP adjustment of ~ 1024 seconds at the same time that the offset is taken but this would be extremely unlikely - I don't believe it deserves any infinite retry loop. That was discussed at the time the enhancement that provides sub-millisecond precision was proposed, and it was rejected in favor of a one time retry.

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PR: https://git.openjdk.java.net/jdk/pull/4016