为什么Akka无法在Java初始化程序中初始化

Question

给出以下代码

import akka.NotUsed;
import akka.actor.ActorRef;
import akka.actor.ActorSystem;
import akka.http.javadsl.ConnectHttp;
import akka.http.javadsl.Http;
import akka.http.javadsl.ServerBinding;
import akka.http.javadsl.model.HttpRequest;
import akka.http.javadsl.model.HttpResponse;
import akka.http.javadsl.server.AllDirectives;
import akka.http.javadsl.server.Route;
import akka.stream.ActorMaterializer;
import akka.stream.javadsl.Flow;

import com.typesafe.config.Config;
import com.typesafe.config.ConfigFactory;

import java.util.concurrent.CompletionStage;

public class Server extends AllDirectives {

    // set up ActorSystem and other dependencies here
    static ActorSystem system; // = ActorSystem.create("pci-enclave");
    static Http http; // = Http.get(system);
    static ActorMaterializer materializer; // = ActorMaterializer.create(system);


    public Server(ActorSystem system) {

    }

    public static void main(String[] args) throws Exception {
        // Create an Actor System in order to materialize HTTP Streams, and other purposes.
        system = ActorSystem.create("foobar");

        http = Http.get(system);
        materializer = ActorMaterializer.create(system);

        // In order to access all route directives we need an instance where the routes are define.
        Server server = new Server(system);

        final Flow<HttpRequest, HttpResponse, NotUsed> routeFlow = server.routeRoot().flow(system, materializer);
        final CompletionStage<ServerBinding> binding = http.bindAndHandle(routeFlow,
            ConnectHttp.toHost("localhost", 8080), materializer);


        System.out.println("Server online at http://localhost:8080/\nPress RETURN to stop...");
        System.in.read(); // let it run until user presses return

        binding
            .thenCompose(ServerBinding::unbind) // trigger unbinding from the port
            .thenAccept(unbound -> system.terminate()); // and shutdown when done
    }

    protected Route routeRoot() {

        return
            route(
                // We can't use static methods because kka.http.javadsl.server.directives.RouteDirectives.route
                // cannot be called in a static context--too bad, so sad. Would have been nicer to just say
            // Foo(system).route(), Bar(system).route()
            new Foo(system).route(),  // http:.../foo/...
            new Bar(system).route()   // http:.../bar/...
        );
    }

}

运行良好；如果我尝试在类初始值设定项中初始化Actor系统，则会得到

[error] (run-main-0) java.lang.ExceptionInInitializerError
java.lang.ExceptionInInitializerError
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:348)
Caused by: com.typesafe.config.ConfigException$Missing: No configuration setting found for key 'akka'

为什么会失败？

在初始化程序中是否有一些特殊的魔术来初始化Akka？

我曾经在Scala中构建Akka系统，但在这种情况下，我需要在Java中构建一些东西。