Got it. But I think the runtime java environment e.g. jdk11 env may cannot optimize these scala lower bytecode very well. However currently no direct report show this problem. hah~
Chesnay Schepler <ches...@apache.org>于2022年5月20日 周五19:53写道： > It's not necessarily required that the scala byte code matches the > version of the java byte code. > > By and large such inconsistencies are inevitable w.r.t. external libraries. > > On 20/05/2022 12:23, Ran Tao wrote: > > Hi, Martijn. Even if we upgrade scala to 2.12.15 to support Java17, it > just > > fix the compilation of FLINK-25000 > > <https://issues.apache.org/jira/browse/FLINK-25000> . There is another > > problem[1] that Scala <=2.13 can't generate jvm11 or higher bytecode > > version. The flink project target class bytecode version is inconsistent > > between scala and java source. > > If we decide to upgrade scala version, how aboout scala 2.12.16, as i > know > > from scala community, the 2.12.16 will backport 2.13 functionilies like > > jvm11,jvm17 target jvm class support. > > > > [1] https://issues.apache.org/jira/browse/FLINK-27549 > > > > Martijn Visser <martijnvis...@apache.org> 于2022年5月20日周五 16:37写道： > > > >> Hi everyone, > >> > >> I would like to get some opinions from our Scala users, therefore I'm > also > >> looping in the user mailing list. > >> > >> Flink currently is tied to Scala 2.12.7. As outlined in FLINK-12461 [1] > >> there is a binary incompatibility introduced by Scala 2.12.8, which > >> currently limits Flink from upgrading to a later Scala 2.12 version. > >> According to the Scala 2.12.8 release notes, "The fix is not binary > >> compatible: the 2.12.8 compiler omits certain methods that are > generated by > >> earlier 2.12 compilers. However, we believe that these methods are never > >> used and existing compiled code will continue to work" > >> > >> We could still consider upgrading to a later Scala 2.12 version, the > latest > >> one currently being 2.12.15. Next to any benefits that are introduced in > >> the newer Scala versions, it would also resolve a blocker for Flink to > add > >> support for Java 17 [2]. > >> > >> My question to Scala users of Flink and others who have an opinion on > this: > >> * Has any of you already manually compiled Flink with Scala 2.12.8 or > >> later? > >> * If so, have you experienced any problems with checkpoint and/or > savepoint > >> incompatibility? > >> * Would you prefer Flink breaking binary compatibility by upgrading to a > >> later Scala 2.12 version or would you prefer Flink to stick with Scala > >> 2.12.7? > >> > >> Note: I know there are also questions about Scala 2.13 and Scala 3 > support > >> in Flink; I think that deserves its own discussion thread. > >> > >> Best regards, > >> > >> Martijn Visser > >> https://twitter.com/MartijnVisser82 > >> https://github.com/MartijnVisser > >> > >> [1] https://issues.apache.org/jira/browse/FLINK-12461 > >> [2] https://issues.apache.org/jira/browse/FLINK-25000 > >> > > > > -- Best, Ran Tao
