public class LocaleSerializeJMHMain2 {

    private static Locale locale = Locale.UK;
    {
        locale.toLanguageTag();
    }

    @Benchmark
    public String localeToString() {
        return locale.toString();
    }

    @Benchmark
    public String localeToLangTag() {
        return locale.toLanguageTag();
    }

    @Benchmark
    public String localeToLangTagWithVersion() {
        return locale.toLanguageTag() + "@";
    }

    public static void main(String[] args) throws RunnerException {
        Options options = new OptionsBuilder()
                .include(LocaleSerializeJMHMain2.class.getSimpleName())
                .warmupIterations(50)
                .forks(1)
                .build();

        new Runner(options).run();
    }

}

// ----------------------------------------------------------------------------------------------------------

Benchmark                                            Mode  Cnt          Score          Error  Units
LocaleSerializeJMHMain2.localeToLangTag             thrpt   20  272830686,501 ± 11221808,760  ops/s  // ±4%
LocaleSerializeJMHMain2.localeToLangTagWithVersion  thrpt   20   21061628,116 ±   983160,887  ops/s  // ±5%
LocaleSerializeJMHMain2.localeToString              thrpt   20   19535473,189 ±  1023500,615  ops/s  // ±5%