JavaFX Script will often be used as the client in multi-tier applications, and will require interoperability with servers. XML and JSON are two very widely used mechanisms for data exchange, so JavaFX Script needs to be able to read, query, manipulate, and write both document forms. In keeping with JavaFX Script’s simplicity and elegance, the XML and JSON frameworks will provide a consistent, simple, and partially declarative way of working with XML and JSON documents. Please visit PlanetJFX to learn more about the JavaFX Script XML framework, and stay tuned for more information on the JSON framework. Also planned are simple, elegant mechanisms of invoking methods on a server by providing consistent frameworks to wrap JSON-RPC and JAX-WS.
Please take a look at this architecture diagram from the Spotting JavaFX Apps in the Wild - A Freebase Browser post:
It shows what I think will be one of the common architectural patterns that employs JavaFX Script as the rich client, in this case with JSON used for data exchange.
JavaFX Script: Dynamic Java Scripting for Rich Internet/Client-side Applications
Immediate eBook (PDF) download available at the book's Apress site