Great news: Lucene 9.4 (optionally) uses mapped MemorySegments when JDK 19 is detected

[Alan Bateman]

On 30/09/2022 08:40, Remi Forax wrote:
> Hi Uwe,
> i wonder if you will not be in trouble when Java 20 will be out with your multi-releases jar,
> because the VM 10 will try to run the bytecodes under the 19 folder and because it is compiled with --enable-preview --source 19, it will not work.
>
> (Alan in CC, to check i'm not saying something stupid.)
>
That's right. JDK 19 with --enable-preview will work. JDK 20 EA builds 
with --enable-preview will fail because the class file version will be 
63.65535 rather than 64.65535. MR JARs are already complicated and it 
would greatly complicate it further if version sections were further 
divided to support classes compiled to make use of preview features. 
I'll bet Uwe/team understand that and they will need to add support for 
JDK 20 anyway. It looks like things are shaping up to have at least some 
shimmer in the j.l.foreign API in Java 20 so they probably have at least 
some work to do.

-Alan