On Thu, 4 Sep 2025 17:17:58 GMT, Chen Liang <[email protected]> wrote:
>> java.lang.invoke has a few Holder classes in DirectMethodHandle,
>> DelegatingMethodHandle, Invokers, and LambdaForm.
>>
>> Currently, the comments simply refer to "Placeholder for xxx generated
>> ahead-of-time".
>>
>> However, they carry executed bytecode and show up in flame graphs. The
>> current comments are definitely not sufficient for their details and
>> purposes.
>>
>> To address these shortcomings, I improved the comments on the Holder classes
>> and GenerateJLIClassesHelper to briefly describe the generation process. In
>> addition, I improved the comments on BoundMethodHandle to provide a more
>> efficient overview.
>
> Chen Liang has updated the pull request incrementally with one additional
> commit since the last revision:
>
> More ioi review
Thanks for improving the documentation! I've left a few suggestions inline.
src/java.base/share/classes/java/lang/invoke/BoundMethodHandle.java line 46:
> 44: /// arguments for currying.
> 45: ///
> 46: /// Each BMH acts like a strongly-typed argument list, where the types are
What do you mean with 'strongly-typed argument list'? Bound method handles are
not just used for arguments.
I'd described BMH as method handles with a number of extra fields that can be
referenced from its lambda form.
src/java.base/share/classes/java/lang/invoke/DelegatingMethodHandle.java line
205:
> 203: ///
> 204: /// The method names of this class are internal tokens recognized by
> 205: /// [InvokerBytecodeGenerator#lookupPregenerated] and is subject to
> change.
Suggestion:
/// [InvokerBytecodeGenerator#lookupPregenerated] and are subject to change.
src/java.base/share/classes/java/lang/invoke/GenerateJLIClassesHelper.java line
58:
> 56: ///
> 57: /// Since lambda forms and bound method handle species are closely tied to
> 58: /// method types, which have many varieties, this generator needs
> *traces* to
Since this is the first mention of 'traces' in this file, I think it would be
great if you could explain what they are, how they are generated (with the
system properties), and what their format are (probably just a link to the
right methods where the printing happens).
src/java.base/share/classes/java/lang/invoke/GenerateJLIClassesHelper.java line
100:
> 98: /// > ```
> 99: /// > javap -c -p -v java.lang.invoke.LambdaForm\$Holder
> 100: /// > ```
I think it is probably enough to put this comment on `javap` here, and it
doesn't need to be on all the holder classes, since the comment there already
links here.
-------------
Marked as reviewed by jvernee (Reviewer).
PR Review: https://git.openjdk.org/jdk/pull/27010#pullrequestreview-3186456503
PR Review Comment: https://git.openjdk.org/jdk/pull/27010#discussion_r2322985931
PR Review Comment: https://git.openjdk.org/jdk/pull/27010#discussion_r2322987321
PR Review Comment: https://git.openjdk.org/jdk/pull/27010#discussion_r2323028010
PR Review Comment: https://git.openjdk.org/jdk/pull/27010#discussion_r2323013426
