Two `Hashtable`'s in `javax.swing.text.html.CSS.LengthUnit` class are modified only within `<clinit>` block: 1. lengthMapping 2. w3cLengthMapping
We can replace them with immutable maps to avoid Hashtable synchronization overhead. ------------- Commit messages: - [PATCH] Unnecessary Hashtable usage in javax.swing.text.html.CSS.LengthUnit Changes: https://git.openjdk.org/jdk/pull/23198/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23198&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8348648 Stats: 21 lines in 1 file changed: 0 ins; 2 del; 19 mod Patch: https://git.openjdk.org/jdk/pull/23198.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/23198/head:pull/23198 PR: https://git.openjdk.org/jdk/pull/23198
