Process for passing required jvm arguments to mill run and test operations

[mrbest]

Can anyone provide an example of how I would pass jvm arguments to _.run and _.test operations in mill?
I am attempting to test and run a spark job from within mill. I am using scala 2.12.30, jdk 17 and spark 3.5.0. I need to pass the jvm argument:

“--add-exports=java.base/sun.nio.ch=ALL-UNNAMED"

to the jvm prior to spark initialization to give spark access to java’s sun.nio.ch.DirectBuffer

What works: The following two examples perform the same execution of the mill _.run operation but I have found no way to directly run _.test operation.

Java call from VS_Code submission

java "--add-exports=java.base/sun.nio.ch=ALL-UNNAMED"
-classpath "/Users/user1/Documents/Development/Projects/IOA /.metals/.tmp/classpath_61BCA15FE47CEDA4CA4B9FD0DF64F75A.jar"
org.ioa.Init
/Users/user1/Documents/Development/Datasrc1/12NOV24
/Users/user1/Documents/Development/Datasrc2/ 12NOV24
/Users/user1/Documents/Development/Datasrc3/input_files/Work _12_04_2024.xlsx
/Users/user1/Documents/Development/Data/IOA/output_files/

Spark-submit:
I am able to run the code using spark-submit with

spark-submit --driver-java-options "--add-exports java.base/sun.nio.ch=ALL-UNNAMED"
/Users/cliftonjbest/Documents/Development/Projects/IOA/out/etl_job/assembly.dest/out.jar
/Users/user1/Documents/Development/Datasrc1/12NOV24
/Users/user1/Documents/Development/Datasrc2/ 12NOV24
/Users/user1/Documents/Development/Datasrc3/input_files/Work _12_04_2024.xlsx
/Users/user1/Documents/Development/Data/IOA/output_files/

What doesn’t work: In all instances below I receive the following error:

“java.lang.IllegalAccessError: class org.apache.spark.storage.StorageUtils$ (in unnamed module @0x59fa0ced) cannot access class sun.nio.ch.DirectBuffer (in module java.base) because module java.base does not export sun.nio.ch to unnamed module”

1. Attempted to add file .mill-jvm-opts to the project root directory.
   file contents: --add-exports=java.base/sun.nio.ch=ALL-UNNAMED

mill myjob.run /Users/cliftonjbest/Documents/Development/Projects/IOA /out/etl_job/assembly.dest/out.jar /Users/user1/Documents/Development/Datasrc1/12NOV24
/Users/user1/Documents/Development/Datasrc2/ 12NOV24
/Users/user1/Documents/Development/Datasrc3/input_files/Work _12_04_2024.xlsx
/Users/user1/Documents/Development/Data/IOA/output_files/

2. Attempted to prepend mill command with JAVA_OPTS=”--add-exports java.base/sun.nio.ch=ALL-UNNAMED”

JAVA_OPTS="--add-exports java.base/sun.nio.ch=ALL-UNNAMED" mill etl_job.run Users/cliftonjbest/Documents/Development/Projects/IOA /out/etl_job/assembly.dest/out.jar /Users/user1/Documents/Development/Datasrc1/12NOV24
/Users/user1/Documents/Development/Datasrc2/ 12NOV24
/Users/user1/Documents/Development/Datasrc3/input_files/Work _12_04_2024.xlsx
/Users/user1/Documents/Development/Data/IOA/output_files/

3. I obtained the same result from when trying to perform the _.test operations using .mill-jvm-opts and setting JAVA_OPTS in-line.

I greatly appreciate any insights that the community can provide in helping me understand the mechanism for passing the "--add-exports=java.base/sun.nio.ch=ALL-UNNAMED” parameter to the process that mill uses to execute the _.run and _.test operations.

[lihaoyi]

If I'm not mistaken, it sounds like you want forkArgs https://mill-build.org/mill/javalib/module-config.html#_compilation_execution_flags

[lihaoyi]

The Mill CLI docs also have a nice breakdown of the different places you can pass args and how to pass them https://mill-build.org/mill/cli/flags.html

[mrbest]

This worked perfectly. I greatly appreciate your reply.