Test actor in akka by java and have ActorInitializationException

I want using from actor test in create actor sample code.but by run actor test throws ActorInitializationException.i am using junit test my class code in under: public class Worker extends AbstractActor {

private ActorSystem system = ActorSystem.create("worker");;
private Props props = Props.create(Worker.class , system.guardian().toString());
private ActorRef actor = system.actorOf(props);

@Override
public void preStart() {
    System.out.println("worker actor started");
}

@Override
public void postStop() {
    System.out.println("worker actor stopped");
}



@Override
public Receive createReceive() {
    return receiveBuilder()
            .matchAny(x -> getSender().tell(x, getSelf()))
            .build();
}


@Test
public void testMain() throws Exception {
    Future sFuture = ask(actor, "ping" , 1000);
    System.out.println("First : " + sFuture);

}


public static void main(String [] args) {
    List<Long> numbers = new ArrayList<>(10);
    for(int i = 0 ; i < 10 ; i++) {
        numbers.add((long) (i+1));
    }
    ActorSystem system = ActorSystem.create("worker");
    for(Long number : numbers) {
        Props props = Props.create(Worker.class , number.toString());
        ActorRef actor = system.actorOf(props);
        actor.tell(number , ActorRef.noSender());
    }
}

}

and exception is:`

akka.actor.ActorInitializationException: You cannot create an instance of [ir.dotin.alm.akka.worker.Worker] explicitly using the constructor (new). You have to use one of the 'actorOf' factory methods to create a new actor. See the documentation.

at akka.actor.ActorInitializationException$.apply(Actor.scala:192)
at akka.actor.Actor$class.$init$(Actor.scala:467)
at akka.actor.AbstractActor.<init>(AbstractActor.scala:132)
at ir.dotin.alm.akka.worker.Worker.<init>(Worker.java:17)
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:408)
at org.junit.runners.BlockJUnit4ClassRunner.createTest(BlockJUnit4ClassRunner.java:187)
at org.junit.runners.BlockJUnit4ClassRunner$1.runReflectiveCall(BlockJUnit4ClassRunner.java:236)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
at org.junit.runners.BlockJUnit4ClassRunner.methodBlock(BlockJUnit4ClassRunner.java:233)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:68)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:47)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)
at org.junit.runners.ParentRunner.run(ParentRunner.java:300)
at org.junit.runner.JUnitCore.run(JUnitCore.java:157)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:117)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:42)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:262)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:84)