A few fail-safe convenience methods added in #23548 are missing necessary null checks. In addition, the `PackageEntry` symbolic conversion and testing methods are not correctly rejecting `PackageDesc` representing the unnamed package, a deliberate choice when `PackageDesc` was added to Java.
Luckily, these oversights can be easily fixed and verified with minor enhancements to existing tests. There are also accompanying minor doc enhancements about the situation. --------- - [x] I confirm that I make this contribution in accordance with the [OpenJDK Interim AI Policy](https://openjdk.org/legal/ai). ------------- Commit messages: - Wording tweak - Match method null check and inconsistencies Changes: https://git.openjdk.org/jdk/pull/31925/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=31925&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8388374 Stats: 69 lines in 5 files changed: 30 ins; 19 del; 20 mod Patch: https://git.openjdk.org/jdk/pull/31925.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/31925/head:pull/31925 PR: https://git.openjdk.org/jdk/pull/31925
