RFR: 8285401: Proxy class initializer should use 3-arg `Class.forName` to avoid unnecessary class initialization [v3]

[liach]

On Tue, 24 May 2022 05:36:30 GMT, Jaikiran Pai <jpai at openjdk.org> wrote:

>> liach has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Move the try catch block as it doesn't throw checked exceptions
>
> src/java.base/share/classes/java/lang/reflect/ProxyGenerator.java line 605:
> 
>> 603:         mv.visitLdcInsn(Type.getObjectType(dotToSlash(className)));
>> 604:         mv.visitMethodInsn(INVOKEVIRTUAL, JL_CLASS,
>> 605:                 "getClassLoader", "()" + LJL_CLASSLOADER, false);
> 
> Hello @liach, should this instead be using the (application supplied) `loader` returned by the call to `ProxyGenerator.getClassLoader()` or maybe the `loader` member in the `ProxyGenerator` itself?

This is equivalent to `jdk.proxy5.$Proxy5.class.getClassLoader()` in Java source code, so this is exactly the application-supplied loader, which also uses the same loader as the previous behavior of `forName` calls.

If you want to pass the loader from `ProxyGenerator` to the proxy, it requires complex tricks. Hidden classes won't work due to serialization incompatibility; accessor methods would be defined in `jdk.internal` and exported specifically to the proxy modules, but writing a class so each proxy gets its loader while what I wrote can already do is overkill.

> test/jdk/java/lang/reflect/Proxy/LazyInitializationTest.java line 56:
> 
>> 54: 
>> 55:         value.m(new Parameter());
>> 56:         Assert.assertTrue(initialized, "parameter type initialized after instantiation");
> 
>> "parameter type initialized after instantiation"
> 
> Since this is the text that gets displayed/reported when the assertion fails, should this instead be "parameter type not initialized"?

The rendered text for testng assert is `message expected: value actual: value`, so on a mismatch, it would print `parameter type initialized after instantiation expected: true actual: false`

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PR: https://git.openjdk.java.net/jdk/pull/8800