RFR [10]: 8186517: sun.nio.cs.StandardCharsets$Aliases and ClassMap can be lazily loaded

[Xueming Shen]

On 08/24/2017 01:00 PM, Claes Redestad wrote:
>
>
> On 2017-08-24 20:06, Claes Redestad wrote:
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> http://cr.openjdk.java.net/~redestad/8186517/jdk.03/
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> Manually verified that generated charsets look correct and ran all charset tests without issue.
>
>>
>> Should be a nice reduction in retained objects on minimal apps.
>
> 425 fewer objects allocated, -16.5Kb.
>
> /Claes

Claes,

It might be worth adding the "instance" field  for the utf-16/be/le as well?  otherwise it
appears a reference to any of the java.nio.charset.StandardCharsets.UTF_8/ISO_8859_1/
US_ASCII will still trigger the mapping loadup in sun.nio.cs.StandardCharsets.

java.nio.charset.Charset.java:642
I doubt the "identity" still works here, does it? can CDS play the magic here?

Take a step back, it might be reasonable to consider to insert the "aliases_xyz"
into individual class directly instead of keeping them in provider ... not sure whether
or not it is worth though, I think we can leave it for next visit :-)

btw, there are some tests at closed test repo for sun/nio/cs need to be run as well. I should
bring them into openjdk when have time.

-Sherman