Java service.getPort thowing NullPointerException JAX-WS

调用service.getPort（HelloInterface.class）时，我得到了一个NullPointerException

网络服务：

@WebService(endpointInterface="com.endpoints.HelloInterface")
public class HelloImpl implements HelloInterface{

    public void sayHello(){
        System.out.println("Hello World!!");
    }
}


@WebService
@SOAPBinding(style = SOAPBinding.Style.RPC)
public interface HelloInterface {

    @WebMethod
    public void sayHello();

}

客户：

public class Launcher {

    public static void main(String[] args) {
        try {
            URL url = new URL("http://localhost:8881/ws/service1?wsdl");
            QName qname = new QName("http://endpoints.com/", "HelloImplService");
            Service service = Service.create(url, qname);
            HelloInterface helloInterface = service
                    .getPort(HelloInterface.class);
        } catch (Exception e) {
            e.printStackTrace();
        }

    }

}

堆栈跟踪：

java.lang.NullPointerException
    at com.sun.xml.internal.ws.model.RuntimeModeler.getPortTypeName(Unknown Source)
    at com.sun.xml.internal.ws.model.RuntimeModeler.getPortTypeName(Unknown Source)
    at com.sun.xml.internal.ws.client.WSServiceDelegate.getPort(Unknown Source)
    at com.sun.xml.internal.ws.client.WSServiceDelegate.getPort(Unknown Source)
    at javax.xml.ws.Service.getPort(Unknown Source)
    at Launcher.main(Launcher.java:14)

在命令提示符下使用wsgen时，我在命令提示符下没有收到任何类型的输出

非常感谢您的帮助