RFR: 8372353: API to compute the byte length of a String encoded in a given Charset [v5]

[Roger Riggs]

On Thu, 15 Jan 2026 14:42:34 GMT, Liam Miller-Cushon <cushon at openjdk.org> wrote:

>> This implements an API to return the byte length of a String encoded in a given charset. See [JDK-8372353](https://bugs.openjdk.org/browse/JDK-8372353) for background.
>> 
>> ---
>> 
>> 
>> Benchmark                              (encoding)  (stringLength)   Mode  Cnt          Score          Error  Units
>> StringLoopJmhBenchmark.getBytes             ASCII              10  thrpt    5  406782650.595 ± 16960032.852  ops/s
>> StringLoopJmhBenchmark.getBytes             ASCII             100  thrpt    5  172936926.189 ±  4532029.201  ops/s
>> StringLoopJmhBenchmark.getBytes             ASCII            1000  thrpt    5   38830681.232 ±  2413274.766  ops/s
>> StringLoopJmhBenchmark.getBytes             ASCII          100000  thrpt    5     458881.155 ±    12818.317  ops/s
>> StringLoopJmhBenchmark.getBytes            LATIN1              10  thrpt    5   37193762.990 ±  3962947.391  ops/s
>> StringLoopJmhBenchmark.getBytes            LATIN1             100  thrpt    5   55400876.236 ±  1267331.434  ops/s
>> StringLoopJmhBenchmark.getBytes            LATIN1            1000  thrpt    5   11104514.001 ±    41718.545  ops/s
>> StringLoopJmhBenchmark.getBytes            LATIN1          100000  thrpt    5     182535.414 ±    10296.120  ops/s
>> StringLoopJmhBenchmark.getBytes             UTF16              10  thrpt    5  113474681.457 ±  8326589.199  ops/s
>> StringLoopJmhBenchmark.getBytes             UTF16             100  thrpt    5   37854103.127 ±  4808526.773  ops/s
>> StringLoopJmhBenchmark.getBytes             UTF16            1000  thrpt    5    4139833.009 ±    70636.784  ops/s
>> StringLoopJmhBenchmark.getBytes             UTF16          100000  thrpt    5      57644.637 ±     1887.112  ops/s
>> StringLoopJmhBenchmark.getBytesLength       ASCII              10  thrpt    5  946701647.247 ± 76938927.141  ops/s
>> StringLoopJmhBenchmark.getBytesLength       ASCII             100  thrpt    5  396615374.479 ± 15167234.884  ops/s
>> StringLoopJmhBenchmark.getBytesLength       ASCII            1000  thrpt    5  100464784.979 ±   794027.897  ops/s
>> StringLoopJmhBenchmark.getBytesLength       ASCII          100000  thrpt    5    1215487.689 ±     1916.468  ops/s
>> StringLoopJmhBenchmark.getBytesLength      LATIN1              10  thrpt    5  221265102.323 ± 17013983.056  ops/s
>> StringLoopJmhBenchmark.getBytesLength      LATIN1             100  thrpt    5  137617873.887 ±  5842185.781  ops/s
>> StringLoopJmhBenchmark.getBytesLength      LATIN1            1000  thrpt    5   92540259.1...
>
> Liam Miller-Cushon has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Update tests

This looks good. 
In the CSR, I'd move the paragraph starting "Computing the..." to the solution section and 
describe the possible optimizations without referring to specific implementation details.
The javadoc in the specification section needs an update. Moving from Draft to Proposed and fixVersion = 27 will get it on the radar of the CSR reviewers.

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PR Comment: https://git.openjdk.org/jdk/pull/28454#issuecomment-3755500610