On Fri, 18 Dec 2020 13:39:48 GMT, Alan Bateman <al...@openjdk.org> wrote:
> Can you look in test/micro for existing examples? Yes, of course, the question is more about the following: should I simply cover `UUID#nameUUIDFromBytes(byte[])` by the benchmark or should I rather write a comparison benchmark which would compare finding the MessageDigest on every iteration against using the holder for this purpose (without any direct reference to `UUID` class). > It might be that the right place to cache is in `MessageDigest` rather than > `UUID` so that other code can benefit too. `UUID.Md5Digest` may be moved to `MessageDigest` but this seems to be a case to implement something similar to this in the way similar to `StandardCharsets`. > One other point is that Standard Algorithms specifies that MD5 is supported > by MessageDigest so the JDK would be broken it could not be found. If the > eventual patch is in UUID then this aspect will need a bit of cleanup. I've looked through [Standard Algorithms section for MessageDigest](https://docs.oracle.com/en/java/javase/15/docs/specs/security/standard-names.html#messagedigest-algorithms) and is says > Algorithm names that *can* be specified And the javadoc of `MessageDigest` says: > Every implementation of the Java platform is required to support the > following standard `MessageDigest` algorithms: > - `SHA-1` > - `SHA-256` So I cannot find any requirement for `MD5` to be present. Although I believe that every implementation does provide it, it may be essential to either specify it or describe the behavior for its absence in case of `UUID`'s usage. ------------- PR: https://git.openjdk.java.net/jdk/pull/1821
