NullPointerException при попытке сохранить мою форму

Я новичок в PlayFramework и просматриваю видеокурс на Udemy. Однако их версия из Play 2.3.9, а я пытаюсь сделать с версией 2.5.4;

При попытке сохранить форму выдает следующую ошибку:

play.api.http.HttpErrorHandlerExceptions$$anon$1: Execution exception[[CompletionException: java.lang.NullPointerException]]
    at play.api.http.HttpErrorHandlerExceptions$.throwableToUsefulException(HttpErrorHandler.scala:280)
    at play.api.http.DefaultHttpErrorHandler.onServerError(HttpErrorHandler.scala:206)
    at play.api.GlobalSettings$class.onError(GlobalSettings.scala:160)
    at play.api.DefaultGlobal$.onError(GlobalSettings.scala:188)
    at play.api.http.GlobalSettingsHttpErrorHandler.onServerError(HttpErrorHandler.scala:98)
    at play.core.server.netty.PlayRequestHandler$$anonfun$2$$anonfun$apply$1.applyOrElse(PlayRequestHandler.scala:100)
    at play.core.server.netty.PlayRequestHandler$$anonfun$2$$anonfun$apply$1.applyOrElse(PlayRequestHandler.scala:99)
    at scala.concurrent.Future$$anonfun$recoverWith$1.apply(Future.scala:344)
    at scala.concurrent.Future$$anonfun$recoverWith$1.apply(Future.scala:343)
    at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:32)
Caused by: java.util.concurrent.CompletionException: java.lang.NullPointerException
    at java.util.concurrent.CompletableFuture.encodeThrowable(CompletableFuture.java:292)
    at java.util.concurrent.CompletableFuture.completeThrowable(CompletableFuture.java:308)
    at java.util.concurrent.CompletableFuture.uniApply(CompletableFuture.java:593)
    at java.util.concurrent.CompletableFuture$UniApply.tryFire(CompletableFuture.java:577)
    at java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:474)
    at java.util.concurrent.CompletableFuture.completeExceptionally(CompletableFuture.java:1977)
    at scala.concurrent.java8.FuturesConvertersImpl$CF.apply(FutureConvertersImpl.scala:21)
    at scala.concurrent.java8.FuturesConvertersImpl$CF.apply(FutureConvertersImpl.scala:18)
    at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:32)
    at scala.concurrent.BatchingExecutor$Batch$$anonfun$run$1.processBatch$1(BatchingExecutor.scala:63)
Caused by: java.lang.NullPointerException: null
    at com.avaje.ebean.Model.save(Model.java:208)
    at controllers.Services.save(Services.java:28)
    at router.Routes$$anonfun$routes$1$$anonfun$applyOrElse$6$$anonfun$apply$6.apply(Routes.scala:227)
    at router.Routes$$anonfun$routes$1$$anonfun$applyOrElse$6$$anonfun$apply$6.apply(Routes.scala:227)
    at play.core.routing.HandlerInvokerFactory$$anon$4.resultCall(HandlerInvoker.scala:157)
    at play.core.routing.HandlerInvokerFactory$$anon$4.resultCall(HandlerInvoker.scala:156)
    at play.core.routing.HandlerInvokerFactory$JavaActionInvokerFactory$$anon$14$$anon$3$$anon$1.invocation(HandlerInvoker.scala:136)
    at play.core.j.JavaAction$$anon$1.call(JavaAction.scala:73)
    at play.http.HttpRequestHandler$1.call(HttpRequestHandler.java:54)
    at play.core.j.JavaAction$$anonfun$7.apply(JavaAction.scala:108)

Моя форма:

@(serviceForm : Form[Service])
@import helper._


@main("Service info"){
  <h1>Service Information</h1>
  @helper.form(action = routes.Services.save()){
    <fieldset>
      <legend>Service</legend>
      @helper.inputText(serviceForm.field("code"), '_label -> "Code")
      @helper.inputText(serviceForm.field("description"), '_label -> "Description")
    </fieldset>
    <input type="submit" value="Save"/>
  }
}

Моя модель:

@Entity
public class Service extends Model {
    @Id
    public String code;
    public String description;

    public String getCode() {
        return code;
    }

    public void setCode(String code) {
        this.code = code;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }
}

Мой контроллер:

public class Services extends Controller {

    @Inject FormFactory formFactory;

    public Result list(){
        return TODO;
    }

    public Result addService(){
        Form<Service> serviceForm = formFactory.form(Service.class);
        return ok(info.render(serviceForm));
    }

    public Result save(){
        Form<Service> serviceForm = formFactory.form(Service.class);
        Service service = serviceForm.bindFromRequest().get();
        service.save();

        return  redirect(routes.Services.addService());
    }
}

Я действительно не знаю, куда идти отсюда. И в Google не так много сообщений, говорящих об этом. Любая помощь будет здорово!

ИЗМЕНИТЬ