RFR: 8141678: sun.invoke.util.Wrapper eagerly initializes all integral type caches

[Claes Redestad]

It's worth considering, but j.l.reflect is already initialized by this point in jake and I saw no real difference in heap dumps or class loading order between this and an experiment where the ZERO constants were simply made public. Adding methods to JavaLangAccess has its own overheads to consider as well.

/Claes


Peter Levart <peter.levart at gmail.com> skrev: (8 november 2015 18:28:03 CET)
>
>
>On 11/08/2015 06:08 PM, Peter Levart wrote:
>>
>>
>> On 11/08/2015 02:43 PM, Claes Redestad wrote:
>>> Hi,
>>>
>>> indy eagerly creates and initializes all integral type caches 
>>> (Byte$ByteCache, Short$ShortCache) which has a small, measurable
>>> impact to jake startup and footprint. Exposing ZERO constants from 
>>> Byte, Character, etc which are guaranteed to be identical to what's
>>> returned from each respective valueOf(0) enables j.l.i. to
>initialize 
>>> without eagerly creating these caches:
>>>
>>> webrev: http://cr.openjdk.java.net/~redestad/8141678/webrev.01
>>> bug: https://bugs.openjdk.java.net/browse/JDK-8141678
>>>
>>> Making these constants public would allow us to not fetch them via 
>>> reflection for a tiny, incremental startup improvement, but I don't
>>> think the constants carry their own weight to motivate them becoming
>
>>> part of public API.
>>
>> Do they have to be the same interned instances as returned from 
>> XXX.valueOf() methods? If not, then constructing new instances could 
>> be cheaper than using reflection which also triggers a bunch cache 
>> initialization (think cached Field object(s) on j.l.Class objects for
>
>> wrapper classes).
>
>I guess they have to be identical instances as returned by
>XXX.valueOf() 
>methods. An alternative to using reflection would be making constants 
>package-private and using SharedSecrets. JavaLangAccess is probably 
>already set when sun.invoke.util.Wrapper is needed by jake or not?
>
>>
>> Regards, Peter
>>
>>>
>>> Testing: verified startup/footprint improvement, various jtreg tests
>>>
>>> /Claes
>>

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