Publish vendor Jar to maven from sbt

build.sbt

// publish to your maven repo using `sbt "myProject/publish"`

// note maven appears to only really support a single jar per library, so create multiple sub-modules

// name of the jar in modules/my-project/lib/<name>.jar
val jarName = "my-vendor-jar"

lazy val myJar = (project in file("modules/my-jar"))
  .settings(
    name := "my-jar",
    ...
    // settings to treat the unmanaged lib jar as the main jar of the published artifact
    (Compile / packageBin) := unmanagedBase.value / s"$jarName.jar",
    artifacts := Classpaths.artifactDefs(List(makePom, Compile / packageBin)).value,
    packagedArtifacts := Classpaths.packaged(List(makePom, Compile / packageBin)).value,
    // shouldn't depend on scala, or be tied to scala version
    autoScalaLibrary := false,
    crossPaths := false
  )

// another sub-project can depend on the jar project, and have the jar available on the classpath
lazy val service = (project in file("modules/service"))
  .dependsOn(myJar)
  .settings(...)