This PR refactors the Double.toHexString method to improve its performance by eliminating the use of StringBuilder and regex operations. The new implementation uses a direct byte array approach to construct the hex string representation, which avoids the overhead of StringBuilder operations and regex pattern matching.
Existing tests in `java/lang/Double/ToHexString.java` cover the float conversions too. ------------- Commit messages: - copyright - copyright - speed up Double.toHexString - add toHexString benchmark Changes: https://git.openjdk.org/jdk/pull/27811/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27811&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8370013 Stats: 91 lines in 2 files changed: 56 ins; 21 del; 14 mod Patch: https://git.openjdk.org/jdk/pull/27811.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/27811/head:pull/27811 PR: https://git.openjdk.org/jdk/pull/27811
