RFR: 8276764: Enable deterministic file content ordering for Jar and Jmod

[Andrew Leonard]

On Mon, 15 Nov 2021 18:47:34 GMT, Andrew Leonard <aleonard at openjdk.org> wrote:

> Both jar and jmod utilise java.io file operations whose methods define no ordering of the return file lists, and in fact rely on OS query file ordering, which can differ by underlying OS architecture.
> This PR adds sort processing to the creation of such jar's and jmod's to enable a deterministic content ordering.
> 
> Signed-off-by: Andrew Leonard <anleonar at redhat.com>

I have tried a couple of performance tests, running a jar of a significant size, repeatedly 100x, results show a 1% difference, although there was some variance on running this several times +/- 5 seconds.
For 100x jar creation of 16,000 files:
Previously : 499 seconds
With patch: 504 seconds

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PR: https://git.openjdk.java.net/jdk/pull/6395