There are many Sun Microsystems technologies that use Ajax [Ajax], and more than one way to use Ajax on mobile platforms. For example, applications written using the Java Platform, Enterprise Edition (Java EE, formerly known as J2EE) may generate XML, JSON [JSON], XHTML and/or ECMAScript destined for mobile browsers.

One of the recent advances on the Java Platform, Mobile Edition (Java ME, formerly known as J2ME) is the Mobile Service Architecture [MSA]. MSA is a Java Specification Request (JSR-248) which defines a set of APIs for Java ME which include a wide variety of features, from Bluetooth to payment, multimedia APIs and support for rich, animated graphics.

This paper discusses an effort to provide Java ME developers with tools to create Mobile Ajax applications, combining the simplicity and familiarity of the Ajax programming model with the richness and secure environment of the MSA APIs. This effort takes the form of an open-source library that can be added to any Java ME application. The paper briefly describes this library along with some sample use cases.

Mobile Ajax For The Java ME Platform
Ajax is typically used in the context of Web applications running in a browser and using XmlHttpRequest from ECMAScript to retrieve XML or JSON data from RESTful Web Services. The results are applied as updates to the current browser’s page DOM (Document Object Model [DOM]).

In the scope of this paper, Mobile Ajax on the Java ME platform is used to mean the following:
? Asynchronous call to the network (using the Mobile Information Device Profile’s [MIDP] Generic Connection Framework [GCF]).
? Use of a data serialization format (such as XML or JSON).
? A presentation layer using a DOM-based User Interface (such as XHTML or SVG). Figure 1 illustrates a typical Mobile Ajax interaction on the Java ME platform.

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