Motivation: When a user passes a wrong parameter, the current implementation throws an IllegalArgumentException with an error message `null`, which is not helpful.
Modification: Add detail error messages. Result: Helpful messages. ------------- Commit messages: - . - chore: add messages for NPE - chore: tweak the error messages - chore: add test cases - 8347491: Add detail error messages when ThreadPoolExecutor's parameter is illegal. Changes: https://git.openjdk.org/jdk/pull/23050/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23050&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8347491 Stats: 164 lines in 3 files changed: 101 ins; 0 del; 63 mod Patch: https://git.openjdk.org/jdk/pull/23050.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/23050/head:pull/23050 PR: https://git.openjdk.org/jdk/pull/23050
