Building a RESTful Web Service with Spring

Asynchronous communication

Another method to help with scalability is using an asynchronous form of communication between the components of a system. Asynchronous communication is a form of communication where a measurable amount of time passes between a request being issued and the availability of the response. For instance, a photographer's portfolio system typically requires generating thumbnails of photos, as well as watermarking originals. These processes can be time consuming, and therefore a synchronous style of communication isn't suitable. The image-processing component of this system would benefit from providing a callback mechanism that notifies you of the tasks' completion.

In addition, by adding this level of abstraction between components, ...