Update

Akka/src/main/scala/core/DriverImpl.scala

@@ -129,7 +129,11 @@ class Driver {
 
                 case LogControllerFinished() =>
                     Behaviors.stopped {() => 
-                        ctx.log.info(f"Average ${(end-initialStart)/(currentTurn-1)} ms")
+                        if (currentTurn > 1) {
+                            ctx.log.info(f"Average ${(end-initialStart)/(currentTurn)} ms")
+                        } else {
+                            ctx.log.info(f"Average ${end-initialStart} ms")
+                        }
                         ctx.log.debug(f"Simulation completes! Stop the driver")
                         workersStop.foreach(a => a ! WorkerSpec.Stop())
                     }

Akka/src/test/scala/simulateUntilTest.scala

@@ -11,7 +11,8 @@ class simulateUntilTest extends FlatSpec {
 
     f"The epidemics example" should "stop as soon as the termination condition is met" in {
       val population = 10000
-      val agents = generated.example.epidemic.InitData(population, 0.01)
+      val graph = cloudcity.lib.Graph.ErdosRenyiGraph(population, 0.01)
+      val agents = generated.example.epidemic.InitData(graph)
       (new API.SimulateUntil()).apply(agents, totalRounds, (ts: Iterable[Iterable[Serializable]]) => {
         val x = ts.last.filter(i => i match {
           case y: generated.example.epidemic.Person => y.health == 1

Base/src/main/scala/Simulate.scala

@@ -48,7 +48,11 @@ object Simulate {
         end = System.currentTimeMillis()
         println(f"Round ${currentRound} takes ${end-start} ms")
       }
-      println(f"Average ${(end - initial)/totalRound} ms")
+      if (totalRound >= 1) {
+        println(f"Average ${(end - initial)/totalRound} ms")
+      } else {
+        println(f"Average ${end - initial} ms")
+      }
       SimulationSnapshot(actors, collectedMessages.flatMap(i => i._2).toList)
     }
 }

build.sbt

@@ -17,6 +17,14 @@ run / fork := true
 
 val pubLocal = Option(System.getProperty("pubLocal")).getOrElse("false")
 
+initialize := {
+  val _ = initialize.value // run the previous initialization
+  val java8 = "1.8"
+  val java11 = "11"
+  val current  = sys.props("java.specification.version")
+  assert(current == java8 || current == java11, s"Unsupported JDK: java.specification.version $current != $java8 or $java11")
+}
+
 lazy val commonSettings = Seq(
   libraryDependencies += "org.scalatest" %% "scalatest" % scalaTestVersion % "test",
   libraryDependencies += "org.scalanlp" %% "breeze" % breezeVersion,