RFR: 8324646: Avoid Class.forName in SecureRandom constructor [v4]

[Oli Gillespie]

On Tue, 6 Feb 2024 13:52:09 GMT, Oli Gillespie <ogillespie at openjdk.org> wrote:

>> Avoid expensive `Class.forName` call when constructing Providers such as `SecureRandom` which take constructor parameters. This can easily be cached in EngineDescription (this cache already existed before, it was removed in [JDK-8280970](https://bugs.openjdk.org/browse/JDK-8280970) as unused, I'm bringing it back unchanged to support this new usage).
>> 
>> Benchmark results on my Linux x86 host show around a 20% reduction in time to create a new `SecureRandom` instance. Most of the remaining overhead is due to a failing constructor lookup - see [JDK-8324648](https://bugs.openjdk.org/browse/JDK-8324648).
>> 
>> 
>> Before
>> newSecureRandom  avgt  2930 ± 50  ns/op
>> 
>> After
>> newSecureRandom  avgt  2400 ± 33  ns/op
>> 
>> 
>> I have seen multiple real-world applications which call `new SecureRandom()` on the hot path, so I believe efficiency here is important.
>
> Oli Gillespie has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Update copyright year

Assuming the approvals still hold after the trivial copyright change, I think this is ready to go. Thanks all.

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PR Comment: https://git.openjdk.org/jdk/pull/17559#issuecomment-1936017246