RFR: 8330467: NoClassDefFoundError when lambda is in a hidden class [v4]

[Mandy Chung]

On Thu, 18 Apr 2024 05:54:17 GMT, Adam Sotona <asotona at openjdk.org> wrote:

>> Current implementation of `LambdaMetafactory` does not allow to use lambdas in hidden classes. Invocation throws `NoClassDefFoundError` instead.
>> 
>> This patch includes lambda implementation in a hidden class under the special handling of `useImplMethodHandle`.
>> The patch also fixes `j/l/i/defineHiddenClass/BasicTest::testLambda` to correctly cover this test case.
>> 
>> Please review.
>> 
>> Thanks,
>> Adam
>
> Adam Sotona has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Update src/java.base/share/classes/java/lang/invoke/InnerClassLambdaMetafactory.java
>   
>   Co-authored-by: Mandy Chung <mandy.chung at oracle.com>

`this::toString` references the hidden class by name [1] which fails to be resolved.   The code needs to ensure that hidden class's name is not referenced for example by casting to a supertype whose is a normal class:


        HiddenTest o = this;
        Supplier<String> s = o::toString;


[1] https://download.java.net/java/early_access/jdk23/docs/api/java.base/java/lang/Class.html#hiddenClasses

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PR Comment: https://git.openjdk.org/jdk/pull/18810#issuecomment-2083336824