Add an `indexOf()` variant allowing to specify both a lower and an upper bound on the search.
------------- Commit messages: - 8302590: Add String.indexOf(int ch, int fromIndex, int toIndex) Changes: https://git.openjdk.org/jdk/pull/12600/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=12600&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8302590 Stats: 245 lines in 4 files changed: 218 ins; 2 del; 25 mod Patch: https://git.openjdk.org/jdk/pull/12600.diff Fetch: git fetch https://git.openjdk.org/jdk pull/12600/head:pull/12600 PR: https://git.openjdk.org/jdk/pull/12600
