Build a SOAP-based Chat Application with Java Web Services, Part 2

art 1 of this tutorial provided a light introduction to the world of Web services. You created a simple SOAP implementation of a Simple Chat server. You also created a client that consumes the chat server's services. This second tutorial extends the original concept of the SimpleChat server with asynchronous messaging.

Asynchronous Invocation
For those new to distributed computing as well as Web services, asynchronous invocation is among the most valuable tools at a developer's disposal when it comes to fine tuning and removing bottlenecks from the system. In the ChatService tutorial, the client application process sends its request to the service and waits for the response message before continuing. This type of synchronous behavior can result in high performance penalties if you're expecting high messaging latency on your network system, either because of traffic congestion, call failures, or server-side delays in processing the response. A more efficient use of client side resources is to send a request and then move the client process along. Later, you can either poll for the response or handle it as a callback reduces traffic and makes. These and related approaches are called "asynchronous invocation." For a more complete and very useful discussion of asynchronous invocation, see Jack Shirazi's Java Performance Tuning.