RFR: 8329581: Java launcher no longer prints a stack trace [v8]

[ExE Boss]

On Mon, 6 May 2024 16:30:11 GMT, Sonia Zaldana Calles <szaldana at openjdk.org> wrote:

>> Hi folks, 
>> 
>> This PR aims to fix [JDK-8329581](https://bugs.openjdk.org/browse/JDK-8329581). 
>> 
>> I think the regression got introduced in [JDK-8315458](https://bugs.openjdk.org/browse/JDK-8315458). 
>> 
>> In the issue linked above, [LauncherHelper#getMainType](https://github.com/openjdk/jdk/pull/16461/files#diff-108a3a3e3c2d108c8c7f19ea498f641413b7c9239ecd2975a6c27d904c2ba226) got removed to simplify launcher code.
>> 
>> Previously, we used ```getMainType``` to do the appropriate main method invocation in ```JavaMain```. However, we currently attempt to do all types of main method invocations at the same time [here](https://github.com/openjdk/jdk/blob/master/src/java.base/share/native/libjli/java.c#L623). 
>> 
>> Note how all of these invocations clear the exception reported with [CHECK_EXCEPTION_FAIL](https://github.com/openjdk/jdk/blob/140f56718bbbfc31bb0c39255c68568fad285a1f/src/java.base/share/native/libjli/java.c#L390). 
>> 
>> Therefore, if a legitimate exception comes up during one of these invocations, it does not get reported. 
>> 
>> I propose reintroducing ```LauncherHelper#getMainType``` but I'm looking forward to your suggestions. 
>> 
>> Cheers, 
>> Sonia
>
> Sonia Zaldana Calles has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Fixing broken uncaught exception mechanism

src/java.base/share/native/libjli/java.c line 639:

> 637:        } else {
> 638:             ret = invokeInstanceMainWithArgs(env, mainClass, mainArgs);
> 639:        }

**Nit:** Wrong indentation[^1]:
Suggestion:

        if (noArgMain) {
            ret = invokeInstanceMainWithoutArgs(env, mainClass);
        } else {
            ret = invokeInstanceMainWithArgs(env, mainClass, mainArgs);
        }


[^1]: (this is one of the reasons I hate when spaces are used to indent things)

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PR Review Comment: https://git.openjdk.org/jdk/pull/18786#discussion_r1591407476