coursier gets stuck

MavenCoursierResolver.scala

package com.example

import MavenCoursierResolver._
import coursier.maven.MavenRepository
import coursier.{Dependency, Module, Platform, Resolution}

import scala.concurrent.duration.DurationInt

class MavenCoursierResolver() {

  private val repositories = MavenRemoteRepositories.getLocalValidRepositories.map(MavenRepository(_))

  private def resolve( dependency: Dependency,
                       filter: Option[Dependency => Boolean] = None,
                       forceVersions: Map[Module, String] = Map.empty): Resolution =
    Resolution(Set(dependency), filter = filter, forceVersions = forceVersions)
      .process
      .run(Platform.fetch(repositories))
      .unsafePerformSyncFor(90.seconds)

  def allDependenciesOf(module: MavenModule): Set[MavenModule] = {
    val coursierDependency = toDependency(module)
    val resolution = resolve(coursierDependency)
    resolution.dependencies.map(toMavenModule) - module
  }
  
  def directDependenciesOf(module: MavenModule): Set[MavenModule] = {
    val coursierDependency = toDependency(module)
    val resolution = resolve(coursierDependency)
    resolution.dependenciesOf(coursierDependency).map(toMavenModule).toSet
  }

}

private case class MavenCoordinates(scope: Scope, packaging: String, module: MavenModule)


object MavenCoursierResolver {
  private def toDependency(mavenModule: MavenModule): Dependency =
    Dependency(Module(mavenModule.groupId, mavenModule.artifactId), mavenModule.version)

  private def toMavenModule(dependency: Dependency) =
    MavenModule(dependency.module.organization, dependency.module.name, dependency.version)

  private def scopeOf(dependency: Dependency) = ScopeTranslation.fromMaven(dependency.configuration)

  private def toMavenModules(dependencies: Set[Dependency]): Set[MavenModule] =
    dependencies.map(toMavenModule)

  private def toMavenModule(dependency: Dependency):MavenModule =
    MavenModule(dependency.module.organization,dependency.module.name,dependency.version)


}

case class MavenModule(groupId:String,artifactId:String,version:String)

MavenCoursierResolverTest.scala

package com.example
import java.nio.file.Paths

import MavenCoursierResolverTest._
import org.specs2.mutable.SpecificationWithJUnit

class MavenCoursierResolverTest extends SpecificationWithJUnit {

  "MavenCoursierResolver" should {
    "Resolve direct dependencies of given maven module" in {
      val module = ExternalModule(
        groupId = "org.eclipse.jetty",
        artifactId = "jetty-server",
        version = "9.4.6.v20170531"
      )
      val directDeps : Set[ExternalModule] = resolver.directDependenciesOf(module)
      val expectedDeps = Set(
        ExternalModule("javax.servlet","javax.servlet-api","3.1.0"),
        ExternalModule("org.eclipse.jetty","jetty-http","9.4.6.v20170531"),
        ExternalModule("org.eclipse.jetty","jetty-io","9.4.6.v20170531")
      )
      directDeps must beEqualTo(expectedDeps)
    }

    "Resolve all dependencies of given maven module" in {
      val module = ExternalModule(
        groupId = "org.eclipse.jetty",
        artifactId = "jetty-server",
        version = "9.4.6.v20170531"
      )
      val allDeps : Set[ExternalModule] = resolver.allDependenciesOf(module)
      val expectedDeps = Set(
        ExternalModule("javax.servlet","javax.servlet-api","3.1.0"),
        ExternalModule("org.eclipse.jetty","jetty-http","9.4.6.v20170531"),
        ExternalModule("org.eclipse.jetty","jetty-io","9.4.6.v20170531"),
        ExternalModule("org.eclipse.jetty","jetty-util","9.4.6.v20170531")
      )
      allDeps must beEqualTo(expectedDeps)
    }

  }
}


object MavenCoursierResolverTest {
  val resolver = new MavenCoursierResolver()
}

MavenRepositories.scala

package com.example

import java.nio.file.{Files, Paths}

import scala.xml.XML

object MavenRemoteRepositories {

  val MavenCentralURL = "https://repo1.maven.org/maven2"

  def onlyMavenCentral = Seq(MavenCentralURL)

  def getLocalValidRepositories: Seq[String] = {
    val settingsPath = Paths.get(sys.props.get("user.home").get,".m2","settings.xml")
    if (!Files.exists(settingsPath)){
      println("warning: settings.xml file not found, using maven central only")
      return Seq.empty
    }
    val xml = XML.load(settingsPath.toUri.toURL)
    MavenCentralURL +: (xml \\ "repositories" \\ "repository" \\ "url").map(_.text)
  }
}