RFR: JDK-8282798 java.lang.runtime.Carrier [v11]

[ExE Boss]

On Mon, 21 Mar 2022 14:24:30 GMT, Jim Laskey <jlaskey at openjdk.org> wrote:

>> We propose to provide a runtime anonymous carrier class object generator; java.lang.runtime.Carrier. This generator class is designed to share anonymous classes when shapes are similar. For example, if several clients require objects containing two integer fields, then Carrier will ensure that each client generates carrier objects using the same underlying anonymous class. 
>> 
>> See JBS for details.
>
> Jim Laskey has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 18 additional commits since the last revision:
> 
>  - Remove LOOKUP static final
>  - Merge branch 'master' into 8282798
>  - Typos
>  - Update Carrier.java
>  - Redo API to use list, bring Carrier.component back
>  - Clean up API
>  - Remove redundant MethodHandle component(MethodType methodType, int i) API
>  - Revert to {@return} style comments.
>  - Clarify primitive store in array carriers.
>  - Use long array for primitives
>  - ... and 8 more: https://git.openjdk.java.net/jdk/compare/7feac45e...a8657bbe

src/java.base/share/classes/java/lang/runtime/Carrier.java line 574:

> 572:             try {
> 573:                 Lookup lookup = MethodHandles.lookup();
> 574:                 return lookup.defineHiddenClass(bytes, false, ClassOption.STRONG);

Actually, this lookup object should probably be kept cached.

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PR: https://git.openjdk.java.net/jdk/pull/7744