RFR: 8302819: Remove JAR Index

[Eirik Bjorsnos]

On Thu, 23 Mar 2023 12:05:50 GMT, Eirik Bjorsnos <duke at openjdk.org> wrote:

> This PR removes the JAR index feature from the runtime:
> 
> - `URLClassPath` is  updated to remove the `enableJarIndex` system property and any code which would be called when this property was `true`
> - The `JarIndex` implementation class is moved into `jdk.jartool` module.
> - The `InvalidJarIndexError` exception class is removed because it falls out of use
> - The test `test/jdk/sun/misc/JarIndex/metaInfFileNames/Basic.java` is removed because it depends on the JarIndex feature being present
> - The test `test/jdk/sun/misc/JarIndex/JarIndexMergeForClassLoaderTest.java` is removed because it depends on the JarIndex feature being present
> - The test `test/jdk/sun/misc/JarIndex/JarIndexMergeTest.java` is removed because it end up being the only caller of the  JarIndex.merge feature
> - All `JarIndex` methods/constructors which are not used by the `jar -i` implementation are removed. 
> - `JarIndex` is given package-private access.
> 
> Outstanding code work:
> 
> - Create tests for `JarFile` and `JarInputStream` accepting dusty INDEX jars.
> 
> Outstanding work:
> 
> - CSR for the removal
> - Release notes for the removal
> - Coordination of the update of the Jar File Specification

If we include the deprecation of `jar -i` in this PR, then the CSR for this PR would need to also cover that deprecation. Same is true for release notes. Not seeing any problem with that myself, but thought it would be good to take note here.

Regarding `JarIndex`:

>Additionally you could even make it package-private there, instead of public. It would anyway need some updates to its javadoc and maybe remove any no longer used methods.

Making it package-private did not work because of the `JarIndexMergeTest` test which directly depends on `JarIndex`. Changing package of the test did not work because of split packages.

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

PR Comment: https://git.openjdk.org/jdk/pull/13158#issuecomment-1481314347
PR Comment: https://git.openjdk.org/jdk/pull/13158#issuecomment-1481730500