RFR: 8294960: Convert java.base/java.lang.invoke package to use the Classfile API to generate lambdas and method handles [v2]

[Chen Liang]

On Sat, 16 Dec 2023 17:28:13 GMT, ExE Boss <duke at openjdk.org> wrote:

>> Adam Sotona has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   added missing comment
>
> src/java.base/share/classes/java/lang/invoke/InnerClassLambdaMetafactory.java line 187:
> 
>> 185:         // generating bridges in the target class)
>> 186:         useImplMethodHandle = (Modifier.isProtected(implInfo.getModifiers()) &&
>> 187:                                !VerifyAccess.isSamePackage(targetClass, implInfo.getDeclaringClass())) ||
> 
> If the `implClass` is hidden, then it’s not possible to generate bytecode which correctly refers to `implMethod`, so the only way is to use the method handle in that case:
> Suggestion:
> 
>         useImplMethodHandle = (Modifier.isProtected(implInfo.getModifiers()) &&
>                                !VerifyAccess.isSamePackage(targetClass, implInfo.getDeclaringClass())) ||
>                                implClass.isHidden() ||

I think this belongs to another RFE and is out of scope of this one. In addition, we need extra tests to invoke the hidden class's lambda to assert its behavioral correctness. Currently, the previously failing test [`LambdaProxyCaller`](https://github.com/openjdk/jdk/blob/master/test/hotspot/jtreg/runtime/cds/appcds/dynamicArchive/test-classes/LambdaProxyCallerIsHiddenApp.java) only creates the hidden class for CDS testing; it doesn't actually invoke the lambda to test its implementation correctness.

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PR Review Comment: https://git.openjdk.org/jdk/pull/17108#discussion_r1428875697