The Hashtable `javax.swing.text.html.parser.Element#contentTypes` is initialized only within `<clinit>` block. We can replace it with immutable map to avoid Hashtable `synchronized` overhead.
------------- Commit messages: - [PATCH] Unnecessary Hashtable usage in javax.swing.text.html.parser.Element Changes: https://git.openjdk.org/jdk/pull/21825/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21825&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8345616 Stats: 16 lines in 1 file changed: 0 ins; 5 del; 11 mod Patch: https://git.openjdk.org/jdk/pull/21825.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/21825/head:pull/21825 PR: https://git.openjdk.org/jdk/pull/21825
