The Java EE 5 Tutorial

Chapter 16 Building Web Services with JAX-WS

JAX-WS stands for Java API for XML Web Services. JAX-WS is a technology for building web services and clients that communicate using XML. JAX-WS allows developers to write message-oriented as well as RPC-oriented web services.

In JAX-WS, a web service operation invocation is represented by an XML-based protocol such as SOAP. The SOAP specification defines the envelope structure, encoding rules, and conventions for representing web service invocations and responses. These calls and responses are transmitted as SOAP messages (XML files) over HTTP.

Although SOAP messages are complex, the JAX-WS API hides this complexity from the application developer. On the server side, the developer specifies the web service operations by defining methods in an interface written in the Java programming language. The developer also codes one or more classes that implement those methods. Client programs are also easy to code. A client creates a proxy (a local object representing the service) and then simply invokes methods on the proxy. With JAX-WS, the developer does not generate or parse SOAP messages. It is the JAX-WS runtime system that converts the API calls and responses to and from SOAP messages.

With JAX-WS, clients and web services have a big advantage: the platform independence of the Java programming language. In addition, JAX-WS is not restrictive: a JAX-WS client can access a web service that is not running on the Java platform, and vice versa. This flexibility is possible because JAX-WS uses technologies defined by the World Wide Web Consortium (W3C): HTTP, SOAP, and the Web Service Description Language (WSDL). WSDL specifies an XML format for describing a service as a set of endpoints operating on messages.

Setting the Port

Several files in the JAX-WS examples depend on the port that you specified when you installed the Application Server. The tutorial examples assume that the server runs on the default port, 8080. If you have changed the port, you must update the port number in the following file before building and running the JAX-WS examples:


Creating a Simple Web Service and Client with JAX-WS

This section shows how to build and deploy a simple web service and client. The source code for the service is in tut-install/javaeetutorial5/examples/jaxws/helloservice/ and the client is in tut-install/javaeetutorial5/examples/jaxws/simpleclient/.

Figure 16–1 illustrates how JAX-WS technology manages communication between a web service and client.

Figure 16–1 Communication between a JAX-WS Web Service and a Client

Diagram showing a client and web service communicating
through a SOAP message.

The starting point for developing a JAX-WS web service is a Java class annotated with the javax.jws.WebService annotation. The @WebService annotation defines the class as a web service endpoint.

A service endpoint interface or service endpoint implementation (SEI) is a Java interface or class, respectively, that declares the methods that a client can invoke on the service. An interface is not required when building a JAX-WS endpoint. The web service implementation class implicitly defines an SEI.

You may specify an explicit interface by adding the endpointInterface element to the @WebService annotation in the implementation class. You must then provide an interface that defines the public methods made available in the endpoint implementation class.

You use the endpoint implementation class and the wsgen tool to generate the web service artifacts that connect a web service client to the JAX-WS runtime. For reference documentation on wsgen, see the Sun Java System Application Server 9.1 Reference Manual.

Together, the wsgen tool and the Application Server provide the Application Server’s implementation of JAX-WS.

    These are the basic steps for creating the web service and client:

  1. Code the implementation class.

  2. Compile the implementation class.

  3. Use wsgen to generate the artifacts required to deploy the service.

  4. Package the files into a WAR file.

  5. Deploy the WAR file. The web service artifacts (which are used to communicate with clients) are generated by the Application Server during deployment.

  6. Code the client class.

  7. Use wsimport to generate and compile the web service artifacts needed to connect to the service.

  8. Compile the client class.

  9. Run the client.

The sections that follow cover these steps in greater detail.

Requirements of a JAX-WS Endpoint

JAX-WS endpoints must follow these requirements:

Coding the Service Endpoint Implementation Class

In this example, the implementation class, Hello, is annotated as a web service endpoint using the @WebService annotation. Hello declares a single method named sayHello, annotated with the @WebMethod annotation. @WebMethod exposes the annotated method to web service clients. sayHello returns a greeting to the client, using the name passed to sayHello to compose the greeting. The implementation class also must define a default, public, no-argument constructor.

package helloservice.endpoint;

import javax.jws.WebService;

public class Hello {
    private String message = new String("Hello, ");

    public void Hello() {}

    public String sayHello(String name) {
        return message + name + ".";

Building, Packaging, and Deploying the Service

You can build, package, and deploy the helloservice application using either NetBeans IDE or ant.

Building, Packaging, and Deploying the Service Using NetBeans IDE

Follow these instructions to build, package, and deploy the helloservice example to your Application Server instance using the NetBeans IDE IDE.

  1. In NetBeans IDE, select File->Open Project.

  2. In the Open Project dialog, navigate to tut-install/javaeetutorial5/examples/jaxws/.

  3. Select the helloservice folder.

  4. Select the Open as Main Project check box.

  5. Click Open Project.

  6. In the Projects tab, right-click the helloservice project and select Undeploy and Deploy.

This builds and packages to application into helloservice.war, located in tut-install/javaeetutorial5/examples/jaxws/helloservice/dist/, and deploys this WAR file to your Application Server instance.

Building, Packaging, and Deploying the Service Using Ant

To build and package helloservice using Ant, in a terminal window, go to the tut-install/javaeetutorial5/examples/jaxws/helloservice/ directory and type the following:


This command calls the default target, which builds and packages the application into an WAR file, helloservice.war, located in the dist directory.

    To deploy the helloservice example, follow these steps:

  1. In a terminal window, go to tut-install/javaeetutorial5/examples/jaxws/helloservice/.

  2. Make sure the Application Server is started.

  3. Run ant deploy.

You can view the WSDL file of the deployed service by requesting the URL http://localhost:8080/helloservice/hello?WSDL in a web browser. Now you are ready to create a client that accesses this service.

Undeploying the Service

At this point in the tutorial, do not undeploy the service. When you are finished with this example, you can undeploy the service by typing this command:

ant undeploy

The all Task

As a convenience, the all task will build, package, and deploy the application. To do this, enter the following command:

ant all

Testing the Service without a Client

    The Application Server Admin Console allows you to test the methods of a web service endpoint. To test the sayHello method of HelloService, do the following:

  1. Open the Admin Console by typing the following URL in a web browser:

  2. Enter the admin user name and password to log in to the Admin Console.

  3. Click Web Services in the left pane of the Admin Console.

  4. Click Hello.

  5. Click Test.

  6. Under Methods, enter a name as the parameter to the sayHello method.

  7. Click the sayHello button.

    This will take you to the sayHello Method invocation page.

  8. Under Method returned, you’ll see the response from the endpoint.

A Simple JAX-WS Client

HelloClient is a stand-alone Java program that accesses the sayHello method of HelloService. It makes this call through a port, a local object that acts as a proxy for the remote service. The port is created at development time by the wsimport tool, which generates JAX-WS portable artifacts based on a WSDL file.

Coding the Client

    When invoking the remote methods on the port, the client performs these steps:

  1. Uses the annotation to declare a reference to a web service. @WebServiceRef uses the wsdlLocation element to specify the URI of the deployed service’s WSDL file.

    static HelloService service;
  2. Retrieves a proxy to the service, also known as a port, by invoking getHelloPort on the service.

    Hello port = service.getHelloPort();

    The port implements the SEI defined by the service.

  3. Invokes the port’s sayHello method, passing to the service a name.

    String response = port.sayHello(name);

Here is the full source of HelloClient, which is located in the tut-install/javaeetutorial5/examples/jaxws/simpleclient/src/java/ directory.

package simpleclient;

import helloservice.endpoint.HelloService;
import helloservice.endpoint.Hello;

public class HelloClient {
    static HelloService service;

    public static void main(String[] args) {
        try {
            HelloClient client = new HelloClient();
        } catch(Exception e) {

    public void doTest(String[] args) {
        try {
            System.out.println("Retrieving the port from
                     the following service: " + service);
            Hello port = service.getHelloPort();
            System.out.println("Invoking the sayHello operation
                     on the port.");

            String name;
            if (args.length > 0) {
                name = args[0];
            } else {
                name = "No Name";

            String response = port.sayHello(name);
        } catch(Exception e) {

Building and Running the Client

You can build and run the simpleclient application using either NetBeans IDE or ant. To build the client, you must first have deployed helloservice, as described in Building, Packaging, and Deploying the Service.

Building and Running the Client in NetBeans IDE

    Do the following to build and run simpleclient:

  1. In NetBeans IDE, select File->Open Project.

  2. In the Open Project dialog, navigate to tut-install/javaeetutorial5/examples/jaxws/.

  3. Select the simpleclient folder.

  4. Select the Open as Main Project check box.

  5. Click Open Project.

  6. In the Projects tab, right-click the simpleclient project and select Run.

You will see the output of the application client in the Output pane.

Building and Running the Client Using Ant

In a terminal navigate to tut-install/examples/jaxws/simpleclient/ and type the following command:


This command calls the default target, which builds and packages the application into a JAR file, simpleclient.jar, located in the dist directory.

The run the client, type the following command:

ant run

Types Supported by JAX-WS

JAX-WS delegates the mapping of Java programming language types to and from XML definitions to JAXB. Application developers don’t need to know the details of these mappings, but they should be aware that not every class in the Java language can be used as a method parameter or return type in JAX-WS. For information on which types are supported by JAXB, see Chapter 17, Binding between XML Schema and Java Classes.

Web Services Interoperability and JAX-WS

JAX-WS 2.0 supports the Web Services Interoperability (WS-I) Basic Profile Version 1.1. The WS-I Basic Profile is a document that clarifies the SOAP 1.1 and WSDL 1.1 specifications to promote SOAP interoperability. For links related to WS-I, see Further Information about JAX-WS.

To support WS-I Basic Profile Version 1.1, the JAX-WS runtime supports doc/literal and rpc/literal encodings for services, static ports, dynamic proxies, and DII.

Further Information about JAX-WS

For more information about JAX-WS and related technologies, see: