In the improvement of @cl4es PR #15591, the advantages of non-lookup-table were discussed.
But if the input is byte[], using lookup table can improve performance. For HexFormat#formatHex(Appendable, byte[]) and HexFormat#formatHex(byte[]), If the length of byte[] is larger, the performance of table lookup will be improved more obviously. ------------- Commit messages: - restore toLowHexDigit & toHighHexDigit - remove unused import - remove AbstractStringBuilder internal method 'appendHex' - Remove redundant code in the benchmark - optimization for HexFormat.formatHex Changes: https://git.openjdk.org/jdk/pull/15768/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15768&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8316426 Stats: 67 lines in 3 files changed: 54 ins; 4 del; 9 mod Patch: https://git.openjdk.org/jdk/pull/15768.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/15768/head:pull/15768 PR: https://git.openjdk.org/jdk/pull/15768
