RFR: 8207329: Add NIL Constant to UUID

Fri Nov 27 18:45:58 UTC 2020

On Fri, 27 Nov 2020 17:55:27 GMT, Roger Riggs <rriggs at openjdk.org> wrote:

>> Adds a constant for the special NIL UUID where all bits are zero to `java.util.UUID`. The [8207329](https://bugs.java.com/bugdatabase/view_bug.do?bug_id=8207329) mentions the usage of it to avoid `null`, it for sure is also very handy in testing where a UUID is required and we do not care about its actual value. Using a random UUID stresses the PRNG for no good reason.
>
> The bug report does not make a strong case for adding a NIL constant to the UUID API.
> It would add (a small amount) to both footprint and startup time with very limited benefit.
> Any application needing a placeholder can do so itself and all existing applications take care of their own needs.

For me it's mostly useful in tests but we cannot ship test only code. We could fix the issues you mention through lazy initialization, or we simply close the PR and ticket and state that the construction via `new UUID(0, 0)` is already simple enough.

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PR: https://git.openjdk.java.net/jdk/pull/1460