How can I build a GraalVM native image shared library?

[ahelwer]

According to the GraalVM docs, you can compile Java code without a main method into a GraalVM native image shared library with a command like:

native-image --shared -o <libraryname> <class name>

However, when I try to add:

graalVMNativeImageOptions := List("--shared", "-o", "LibName")

to my build.sbt file then run GraalVMNativeImage/packageBin, it just outputs:

[error] (Graalvm-native-image / packageBin) Could not find a main class.

Here is my build.sbt:

enablePlugins(GraalVMNativeImagePlugin)
Compile / javaSource := baseDirectory.value / "src"
Test / javaSource := baseDirectory.value / "test"
graalVMNativeImageOptions := List("--shared", "-o", "TlaLib")
libraryDependencies += "net.aichler" % "jupiter-interface" % "0.11.1" % Test

Here is my project/plugins.sbt:

addSbtPlugin("net.aichler" % "sbt-jupiter-interface" % "0.11.1")
addSbtPlugin("com.github.sbt" % "sbt-native-packager" % "1.11.1")

And here is the contents of the only non-test source file, src/tla/Lib.java:

package tla;

public class Lib {
  public static String getMessage() {
    return "Hello, world!";
  }
}

How can I get this to compile into a shared library? Thank you!