RFR: 8342513: Autoboxing Overhead & Inefficient Parallel Processing

[wasif kirmani]

[JDK-8342513](https://bugs.openjdk.org/browse/JDK-8342513) : Autoboxing Overhead & Inefficient Parallel Processing

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Commit messages:
 - 8342513 : Fixed autoboxing and aprallel processing for big dataset

Changes: https://git.openjdk.org/jdk/pull/21566/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21566&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8342513
  Stats: 77 lines in 3 files changed: 28 ins; 9 del; 40 mod
  Patch: https://git.openjdk.org/jdk/pull/21566.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21566/head:pull/21566

PR: https://git.openjdk.org/jdk/pull/21566