To use the JAX-WS frontend, an SEI must be annotated using standardised JAX-WS annotations. The annotations signal to the Web services tooling that the SEI uses JAX-WS and the annotations are also used to customize the mapping from Java to WSDL. Here we only cover the most basic annotations—for complete details of JAX-WS annotations, see Developing Applications Using JAX-WS from the Apache CXF library.

	Note
	It sometimes makes sense also to annotate the service implementation class (the class that implements the SEI)—for example, if you want to associate an implementation class with a specific WSDL serviceName and portName (there can be more than one implementation of a given SEI).

The minimal annotation required for an SEI using the JAX-WS frontend is to prefix the interface declaration with @WebService. For example, the CustomerService SEI could be minimally annotated as follows:

// Java
package com.fusesource.demo.wsdl.customerservice;

import javax.jws.WebService;
 
@WebService
public interface CustomerService {
  ...
}

If you run the Java-to-WSDL utility on this interface, it will generate a complete WSDL contract using the standard default style of code conversion.

Although it is sufficient to specify the @WebService annotation without any attributes, it is usually better to specify some attributes to provide a more descriptive WSDL service name and WSDL port name. You will also usually want to specify the XML target namespace. For this, you can specify the following optional attributes of the @WebService annotation:

You can add the @WebParam annotation to method arguments in the SEI. The @WebParam annotation is optional, but there are a couple of good reasons for adding it:

You can add @WebParam annotations with the following attributes:

In WSDL, OUT and INOUT parameters represent values that can be sent from the service back to the client (where the INOUT parameter is sent in both directions).

In Java syntax, the only value that can ordinarily be returned from a method is the method's return value. In order to support OUT or INOUT parameters in Java (which are effectively like additional return values), you must:

The following example shows the CustomerService SEI after it has been annotated. Many other annotations are possible, but this level of annotation is usually adequate for a WSDL-first project.

// Java
package com.fusesource.demo.wsdl.customerservice;

import javax.jws.WebParam;
import javax.jws.WebService;
 
@WebService(
  targetNamespace = "http://demo.fusesource.com/wsdl/CustomerService/",
  name = "CustomerService",
  serviceName = "CustomerService",
  portName = "SOAPOverHTTP"
)
public interface CustomerService {

    public com.fusesource.demo.customer.Customer lookupCustomer(
        @WebParam(name = "customerId", targetNamespace = "")
        java.lang.String customerId
    );

    public void updateCustomer(
        @WebParam(name = "cust", targetNamespace = "")
        com.fusesource.demo.customer.Customer cust
    );

    public void getCustomerStatus(
        @WebParam(name = "customerId", targetNamespace = "")
        java.lang.String customerId,
        @WebParam(mode = WebParam.Mode.OUT, name = "status", targetNamespace = "")
        javax.xml.ws.Holder<java.lang.String> status,
        @WebParam(mode = WebParam.Mode.OUT, name = "statusMessage", targetNamespace = "")
        javax.xml.ws.Holder<java.lang.String> statusMessage
    );
}