8341184: Clean up the interaction between the launcher native code and the LauncherHelper

[jaikiran]

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.

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Progress

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Issue

• JDK-8341184: Clean up the interaction between the launcher native code and the LauncherHelper (Bug - P4)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/21256/head:pull/21256
$ git checkout pull/21256

Update a local copy of the PR:
$ git checkout pull/21256
$ git pull https://git.openjdk.org/jdk.git pull/21256/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 21256

View PR using the GUI difftool:
$ git pr show -t 21256

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/21256.diff

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