RFR: 8342642: Class loading failure due to archived map issue in ModuleLoaderMap.Mapper

[Jiangli Zhou]

On Fri, 25 Oct 2024 21:25:54 GMT, Jiangli Zhou <jiangli at openjdk.org> wrote:

> Moved from https://github.com/openjdk/jdk/pull/21672/commits/ade90fb51d1e3652910a3b46775522b730306e16:
> 
> Please review the fix that uses String type for the mapped value in ModuleLoaderMap.Mapper map (Map<String, String>). Please see details in https://bugs.openjdk.org/browse/JDK-8342642, thanks.
> 
> Existing comment threads from closed https://github.com/openjdk/jdk/pull/21672/commits/ade90fb51d1e3652910a3b46775522b730306e16:
> - https://github.com/openjdk/jdk/pull/21672#issuecomment-2436358591
> - https://github.com/openjdk/jdk/pull/21672#issuecomment-2437465648
> - https://github.com/openjdk/jdk/pull/21672#issuecomment-2438567642
> - https://github.com/openjdk/jdk/pull/21672#issuecomment-2436262114
> - https://github.com/openjdk/jdk/pull/21672#issuecomment-2437501231

Follow up of the `==` and `.equals()` discussion:

I ran a comparison using HelloWorld on my Linux machine. The difference looks noise.

- With '=='
    Performance counter stats for 'images/jdk/bin/java -cp /.../home/jianglizhou/tests/hw.jar HelloWorld' (100 runs):

               133.08 msec task-clock:u                     #    1.181 CPUs utilized               ( +-  0.29% )
                    0      context-switches:u               #    0.000 /sec
                    0      cpu-migrations:u                 #    0.000 /sec
                5,940      page-faults:u                    #   44.636 K/sec                       ( +-  0.02% )
          139,151,067      cycles:u                         #    1.046 GHz                         ( +-  0.24% )
          158,618,665      instructions:u                   #    1.14  insn per cycle              ( +-  0.00% )
           27,343,220      branches:u                       #  205.471 M/sec                       ( +-  0.00% )
              746,103      branch-misses:u                  #    2.73% of all branches             ( +-  0.63% )

             0.112697 +- 0.000386 seconds time elapsed  ( +-  0.34% ).

 -  With '.equals()':
    Performance counter stats for 'images/jdk/bin/java -cp /usr/local/google/home/jianglizhou/tests/hw.jar HelloWorld' (100 runs):

               133.26 msec task-clock:u                     #    1.186 CPUs utilized               ( +-  0.34% )
                    0      context-switches:u               #    0.000 /sec
                    0      cpu-migrations:u                 #    0.000 /sec
                5,941      page-faults:u                    #   44.581 K/sec                       ( +-  0.02% )
          141,082,552      cycles:u                         #    1.059 GHz                         ( +-  0.25% )
          158,619,823      instructions:u                   #    1.12  insn per cycle              ( +-  0.00% )
           27,343,260      branches:u                       #  205.184 M/sec                       ( +-  0.00% )
              743,257      branch-misses:u                  #    2.72% of all branches             ( +-  0.68% )

             0.112399 +- 0.000505 seconds time elapsed  ( +-  0.45% )

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

PR Comment: https://git.openjdk.org/jdk/pull/21722#issuecomment-2438908920