Hello,
I kept forgetting which variants of the String methods perform better
with single-char-Strings and which with char (IDEs had the tendency to
suggest the wrong variant since it changed between JDK releases). So i
wrote JMH benchmarks and noticed that the last method with a performance
difference seems to be String.indexOf() - all other variants performed
equally (unless I overlooked some).
this might be fairly easy to fix:
https://github.com/openjdk/jdk/pull/6509
(side effect: contains("c") is also faster)
I haven't looked into the intrinsified code of StringLatin1 and
StringUTF16 to check if it could be fixed there (mostly because i
actually don't know how the JVM assembles those intrinsics). It might be
possible to improve this for short Strings in general, not just for
chars, dependent on why the intrinsified version is actually slower for
single-char-Strings. I opted for the trivial fix in java code.
best regards,
michael
