he recently launched Eclipse Rich Ajax Platform (RAP) is another component of the ever-increasing Eclipse ecosystem. Its purpose, as explained on the Eclipse RAP website, is simple: "The RAP project enables developers to build rich, Ajax-enabled Web applications by using the Eclipse development model, plug-ins with the well known Eclipse workbench extension points, and a widget toolkit with SWT API."

Eclipse RAP delivers this functionality to enable a three-pronged vision:

• Allow developers to reuse as much knowledge as possible from their experience with the Eclipse Rich Client Platform (RCP) applications
• Have only one codebase for both rich client applications and server-side applications accessed through a browser
• Facilitate the notoriously difficult debugging of web applications by operating completely on Java code on the server side

The final result offers two main advantages for the developer and the user:

• The developer has to learn (almost) nothing in addition to what he or she already knows about Eclipse RCP, and he or she uses exactly the same programming paradigm. For an RCP developer, the learning curve for developing RAP applications is negligible.
• The user gains a new way of interacting with the application, which looks and behaves similarly to a standard RCP application but requires only a web browser.

This article introduces the basics of Eclipse RAP and explains its similarities and differences with Eclipse RCP. It then walks through real-world examples for using it in your web development. If you haven't developed RCP applications before, you can learn RAP here first and then apply what you've learned in the RCP realm.