RFR: 8341184: Clean up the interaction between the launcher native code and the LauncherHelper [v16]

[Shaojin Wen]

On Mon, 24 Feb 2025 09:46:29 GMT, Jaikiran Pai <jpai at openjdk.org> wrote:

>> Can I please get a review of this change, which simplifies the interaction between the `java` launcher's native code with the `sun.launcher.LauncherHelper`? 
>> 
>> As noted in https://bugs.openjdk.org/browse/JDK-8341184, this proposed change reduces the back and forth between the launcher's native code and the `LauncherHelper` class. This also removes the additional reflective lookups from the native code after the main class and main method have been determined by the `LauncherHelper`. 
>> 
>> Although this is a clean up of the code, the changes in the `LauncherHelper` to return a `MainEntry` have been done in a way to facilitate additional upcoming changes in this area, which propose to get rid of the JAR manifest parsing from the launcher's native code.
>> 
>> No new tests have been added. Existing tests in tier1, tier2 and tier3 continue to pass.
>
> Jaikiran Pai has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 16 commits:
> 
>  - merge latest from master branch
>  - merge latest from master branch
>  - merge latest from master branch
>  - merge latest from master branch
>  - merge latest from master branch
>  - merge latest from master branch
>  - merge latest from master branch
>  - merge latest from master branch
>  - merge latest from master branch
>  - merge latest from master branch
>  - ... and 6 more: https://git.openjdk.org/jdk/compare/e410af00...d1ac5174

src/java.base/share/classes/sun/launcher/LauncherHelper.java line 946:

> 944:                         JAVAFX_APPLICATION_CLASS_NAME);
> 945:             }
> 946:         }

Suggestion:

        if (!PreviewFeatures.isEnabled()) {
            int mods = mainMethod.getModifiers();
            if (!Modifier.isStatic(mods) || !Modifier.isPublic(mods) || mainMethod.getParameterCount() == 0) {
                abort(null, "java.launcher.cls.error2", builder.mainClass.getName(),
                        JAVAFX_APPLICATION_CLASS_NAME);
            }
        }

Remove variables that are only used once

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/21256#discussion_r2076992705