$ cat test.scala
import scala.tools.nsc.interpreter.IMain

object Test extends App {
  val cl = Thread.currentThread().getContextClassLoader
  println(cl)

  val imain = new IMain()
  imain.interpret("println(42)")
 
  val cl2 = Thread.currentThread().getContextClassLoader
  println(cl2)

  println(cl == cl2)
}
$ scala Test
scala.reflect.internal.util.ScalaClassLoader$URLClassLoader@1f32e575
42
scala.reflect.internal.util.ScalaClassLoader$URLClassLoader@1f32e575
true

    sbt.ForkMain$ForkError: interface akka.actor.Scheduler is not assignable from class akka.actor.LightArrayRevolverScheduler
            at akka.actor.ReflectiveDynamicAccess$$anonfun$getClassFor$1.apply(DynamicAccess.scala:69)
            at akka.actor.ReflectiveDynamicAccess$$anonfun$getClassFor$1.apply(DynamicAccess.scala:66)
            at scala.util.Try$.apply(Try.scala:191)
            at akka.actor.ReflectiveDynamicAccess.getClassFor(DynamicAccess.scala:66)
            at akka.actor.ReflectiveDynamicAccess.createInstanceFor(DynamicAccess.scala:84)
            at akka.actor.ActorSystemImpl.createScheduler(ActorSystem.scala:676)
            at akka.actor.ActorSystemImpl.<init>(ActorSystem.scala:576)
            at akka.actor.ActorSystem$.apply(ActorSystem.scala:142)
            at akka.actor.ActorSystem$.apply(ActorSystem.scala:109)
            at foo.bar.SomeSpec.<init>(SomeSpec.scala:32)
            at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
            at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
            at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
            at java.lang.reflect.Constructor.newInstance(Constructor.java:422)
            at java.lang.Class.newInstance(Class.java:442)
            at org.scalatest.tools.Framework$ScalaTestTask.execute(Framework.scala:641)
            at sbt.ForkMain$Run$2.call(ForkMain.java:294)
            at sbt.ForkMain$Run$2.call(ForkMain.java:284)
            at java.util.concurrent.FutureTask.run(FutureTask.java:266)
            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
            at java.lang.Thread.run(Thread.java:745)

package foo

import javax.script.ScriptEngineManager

object Main extends App {

  val ngine = new ScriptEngineManager().getEngineByName("scala")

  val iMain = ngine.asInstanceOf[scala.tools.nsc.interpreter.IMain]
  class Foo
  iMain.settings.embeddedDefaults[Foo]

  println(Thread.currentThread().getContextClassLoader)
  iMain.compile("val x = 1")
  println(Thread.currentThread().getContextClassLoader)

}

      // work-around for SI-8521 (Scala 2.11.0)
      override def interpret(line: String, synthetic: Boolean): Results.Result = {
        val th = Thread.currentThread()
        val cl = th.getContextClassLoader
        try {
          super.interpret(line, synthetic)
        } finally {
          th.setContextClassLoader(cl)
        }
      }