Java web service without a web application server

You don't need a third party library to use jax-ws annotations. J2SE ships with jax-ws, so all the annotations are still available to you. You can achieve lightweight results with the following solution, but for anything optimized/multi-threaded, it's on your own head to implement:

  1. Design a SEI, service endpoint interface, which is basically a java interface with web-service annotations. This is not mandatory, it's just a point of good design from basic OOP.

    import javax.jws.WebService;
    import javax.jws.WebMethod;
    import javax.jws.WebParam;
    import javax.jws.soap.SOAPBinding;
    import javax.jws.soap.SOAPBinding.Style;
    
    @WebService
    @SOAPBinding(style = Style.RPC) //this annotation stipulates the style of your ws, document or rpc based. rpc is more straightforward and simpler. And old.
    public interface MyService{
    @WebMethod String getString();
    
    }
    
  2. Implement the SEI in a java class called a SIB service implementation bean.

    @WebService(endpointInterface = "com.yours.wsinterface") //this binds the SEI to the SIB
    public class MyServiceImpl implements MyService {
    public String getResult() { return "result"; }
     }
    
  3. Expose the service using an Endpoint import javax.xml.ws.Endpoint;

    public class MyServiceEndpoint{
    
    public static void main(String[] params){
      Endpoint endPoint =  EndPoint.create(new MyServiceImpl());
      endPoint.publish("http://localhost:9001/myService"); //supply your desired url to the publish method to actually expose the service.
       }
    }
    

The snippets above, like I said, are pretty basic, and will perform poorly in production. You'll need to work out a threading model for requests. The endpoint API accepts an instance of Executor to support concurrent requests. Threading's not really my thing, so I'm unable to give you pointers.