Harmless illegal reflective access warning with JDK 11 (but not 8 or 17+)

[xuwei-k]

$ java --version 
openjdk 11.0.21 2023-10-17 LTS
OpenJDK Runtime Environment Zulu11.68+17-CA (build 11.0.21+9-LTS)
OpenJDK 64-Bit Server VM Zulu11.68+17-CA (build 11.0.21+9-LTS, mixed mode)
$ scala          
Welcome to Scala 2.13.13 (OpenJDK 64-Bit Server VM, Java 11.0.21).
Type in expressions for evaluation. Or try :help.
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by org.jline.terminal.impl.exec.ExecTerminalProvider$ReflectionRedirectPipeCreator to constructor java.lang.ProcessBuilder$RedirectPipeImpl()
WARNING: Please consider reporting this to the maintainers of org.jline.terminal.impl.exec.ExecTerminalProvider$ReflectionRedirectPipeCreator
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release

[SethTisue]

cause is jline/jline3#862 , so we may need to move to JLine 3.25.1 in order to fix it 😕

[SethTisue]

At least it's specific to 11! Doesn't happen on 8, 17, or 21.

[SethTisue]

Also the REPL seems to work fine anyway, at least as far as I can tell — I've added “harmless” to the issue title, hopefully I won't have to remove it again 🤞

[hamzaremmal]

@SethTisue FYI: Scala 3 has been updated to used JLine 3.25.1 (in scala/scala3#19744)

[irisTa56]

I encountered the same kind of warning when I used HEAD of Scala 2.13.x branch. (I'm using macOS 14.4.1)

sbt:root> scala
[info] running (fork) scala.tools.nsc.MainGenericRunner -usejavacp
Welcome to Scala 2.13.14-20240410-192757-770e6a0 (OpenJDK 64-Bit Server VM, Java 11.0.22).
Type in expressions for evaluation. Or try :help.
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by org.jline.terminal.impl.exec.ExecTerminalProvider$ReflectionRedirectPipeCreator (file:/Users/takayuki.kobayashi/Documents/_repos/scala/target/bg-jobs/sbt_86d39714/target/34c75c8d/1c1c671a/jline-3.25.1.jar) to constructor java.lang.ProcessBuilder$RedirectPipeImpl()
WARNING: Please consider reporting this to the maintainers of org.jline.terminal.impl.exec.ExecTerminalProvider$ReflectionRedirectPipeCreator
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release

The warning seems the same as the one I saw in v2.13.13.

sbt:root> scala
[info] running (fork) scala.tools.nsc.MainGenericRunner -usejavacp
Welcome to Scala 2.13.13-20240221-035612-fcc67cd (OpenJDK 64-Bit Server VM, Java 11.0.22).
Type in expressions for evaluation. Or try :help.
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by org.jline.terminal.impl.exec.ExecTerminalProvider$ReflectionRedirectPipeCreator (file:/Users/takayuki.kobayashi/Documents/_repos/scala/target/bg-jobs/sbt_60ac3d2e/target/852a93e8/04359738/jline-3.24.1.jar) to constructor java.lang.ProcessBuilder$RedirectPipeImpl()
WARNING: Please consider reporting this to the maintainers of org.jline.terminal.impl.exec.ExecTerminalProvider$ReflectionRedirectPipeCreator
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release

Since JLine v3.24.1 already has jline/jline3#862, I think it seems related to jline/jline3#951.

Note that for sbt, I could suppress the warning by setting the system property sbt/sbt#7505 (comment), but it didn't take effect for scala inside sbt.

[SethTisue]

@irisTa56 perhaps it will go away once sbt takes the 3.25.1 upgrade — we're pursuing it at sbt/sbt#7500

I don't see the warning if I sbt dist/mkPack followed by ./build/pack/bin/scala

currently the REPL you get from scala command inside sbt in the Scala 2 build is messed up anyway, as per scala/scala-dev#755

[irisTa56]

@SethTisue
Thank you for your reply.
I will wait for the sbt upgrade.