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Java properties

Although the Scala CLI runner can be used as a native image and thus will not always be run on the JVM it still supports Java properties. There are a couple ways to specify them.

On the Command line​

Java properties can be passed as arguments, before the sub-command name and sources, when invoking scala-cli, e.g.

    scala-cli '-Dcoursier.credentials=maven.pkg.github.com Private_Token:gh_token1234' run .
note
  • scala-cli run . -Dfoo=bar would pass the java property into your Scala app
  • scala-cli -Dfoo=bar run . would pass the java property into scala-cli.

File named .scala-jvmopts​

You can also use a .scala-jvmopts file placed in the project's root, example file content:

-Dcoursier.credentials=maven.pkg.github.com Private_Token:gh_token1234
-Dhttp.proxy=4.4.4.4
-Dhttp.user=User2

Scala CLI's config​

It's also possible to use the config subcommand to set the properties globally:

    scala-cli --power config -i java.properties "http.proxy=4.4.4.4" "http.user=User2" "coursier.credentials=..."
note

Please note that if you need to modify the Java properties, you have to redefine all of them. It's not possible to update just a single value via the config command. Each update effectively replaces the entire Java properties list.

JAVA_OPTS and JDK_JAVA_OPTIONS​

Scala CLI will also read environment variables JAVA_OPTS and JDK_JAVA_OPTIONS and scan them for Java properties:

    export JAVA_OPTS="-Dhttp.proxy=4.4.4.4 -Dhttp.user=User2"
note

The -D prefix can only be dropped when writing the values to config.