Preface

This is a book for programmers interested in developing Java web services and Java clients against web services, whatever the implementation language. The book is a code-driven introduction to JAX-WS (Java API for XML-Web Services), the framework of choice for Java web services, whether SOAP-based or REST-style. My approach is to interpret JAX-WS broadly and, therefore, to include leading-edge developments such as the Jersey project for REST-style web services, officially known as JAX-RS (Java API for XML-RESTful Web Services).

JAX-WS is bundled into the Metro Web Services Stack, or Metro for short. Metro is part of core Java, starting with Standard Edition 6 (hereafter, core Java 6). However, the Metro releases outpace the core Java releases. The current Metro release can be downloaded separately from https://wsit.dev.java.net. Metro is also integrated into the Sun application server, GlassFish. Given these options, this book’s examples are deployed in four different ways:

Core Java only

This is the low-fuss approach that makes it easy to get web services and their clients up and running. The only required software is the Java software development kit (SDK), core Java 6 or later. Web services can be deployed easily using the Endpoint, HttpServer, and HttpsServer classes. The early examples take this approach.

Core Java with the current Metro release

This approach takes advantage of Metro features not yet available in the core Java bundle. In general, each Metro release makes it easier to write web services and clients. The current Metro release also indicates where JAX-WS is moving. The Metro release also can be used with core Java 5 if core Java 6 is not an option.

Standalone Tomcat

This approach builds on the familiarity among Java programmers with standalone web containers such as Apache Tomcat, which is the reference implementation. Web services can be deployed using a web container in essentially the same way as are servlets, JavaServer Pages (JSP) scripts, and JavaServer Faces (JSF) scripts. A standalone web container such as Tomcat is also a good way to introduce container-managed security for web services.

GlassFish

This approach allows deployed web services to interact naturally with other enterprise components such as Java Message Service topics and queues, a JNDI (Java Naming and Directory Interface) provider, a backend database system and the @Entity instances that mediate between an application and the database system, and an EJB (Enterprise Java Bean) container. The EJB container is important because a web service can be deployed as a stateless Session EJB, which brings advantages such as container-managed thread safety. GlassFish works seamlessly with Metro, including its advanced features, and with popular IDEs (Integrated Development Environment) such as NetBeans and Eclipse.

An appealing feature of JAX-WS is that the API can be separated cleanly from deployment options. One and the same web service can be deployed in different ways to suit different needs. Core Java alone is good for learning, development, and even lightweight deployment. A standalone web container such as Tomcat provides additional support. A Java application server such as GlassFish promotes easy integration of web services with other enterprise technologies.