When comparing a `MemorySegment` to `MemorySegment.NULL` using `==`, the comparison may fail because a segment with address `0` can be created independently and will therefore have a different identity from `MemorySegment.NULL`.
This PR adds JavaDocs that explain this issue and warn against using `==` to compare segments to `MemorySegment.NULL`. ------------- Commit messages: - Add javadocs about null memorysegments Changes: https://git.openjdk.org/jdk/pull/30501/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=30501&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8381012 Stats: 12 lines in 1 file changed: 12 ins; 0 del; 0 mod Patch: https://git.openjdk.org/jdk/pull/30501.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/30501/head:pull/30501 PR: https://git.openjdk.org/jdk/pull/30501
