Java web services are used to build applications that communicate with each other over a network, using the principles of the World Wide Web. Here is a simple example of a Java web service that you can use as a starting point:

1. First, create a Java class that represents the service. This class should have a method that returns the result of the service. For example:

import javax.jws.WebService;

@WebService
public class HelloService {
    public String sayHello(String name) {
        return "Hello, " + name + "!";
    }
}

2. Next, create a web service endpoint interface (SEI) that defines the service. The SEI should extend the javax.jws.WebService interface and define the method of the service. For example:

import javax.jws.WebMethod;
import javax.jws.WebService;
import javax.jws.soap.SOAPBinding;

@WebService
@SOAPBinding(style = SOAPBinding.Style.RPC)
public interface HelloServiceSEI {
    @WebMethod
    String sayHello(String name);
}

3. Next, create a web service implementation class that implements the SEI and the service class. This class should have a default constructor and should annotate the implementation class with the javax.jws.WebService annotation. For example:

import javax.jws.WebService;

@WebService(endpointInterface = "HelloServiceSEI")
public class HelloServiceImpl implements HelloServiceSEI {
    public String sayHello(String name) {
        return new HelloService().sayHello(name);
    }
}

4. Finally, create a web service deployer class that deploys the web service on a web server. This class should use the javax.xml.ws.Endpoint class to publish the web service. For example:

import javax.xml.ws.Endpoint;

public class HelloServiceDeployer {
    public static void main(String[] args) {
        Endpoint.publish("http://localhost:8080/hello", new HelloServiceImpl());
    }
}

To test the web service, you can use a tool such as SoapUI to send a request to the web service and receive a response.