 ava Web Start provides a mechanism for one-touch downloading and installation of applications across the Web. It is based on the Java Network Launching Protocol and API (JNLP), a standard API for application downloading and launching. Think of Java Web Start as a reference implementation of a system that uses JNLP.
Like an applet, a Java Web Start application resides in, and is invoked from, a Web page. However, unlike an applet, a Java Web Start application is stored permanently once it has been downloaded so you can use Java Web Start to distribute large, full-featured applications that would be too large to distribute as applets. Java Web Start also transparently handles software updates, which simplifies the distribution of new application versions to users.
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Figure 1. Thingy | This simple graphical toy is the sample Java Web Start application you'll deploy.
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In this article, you'll learn how to create and deploy a Java Web Start application from start to finish. I'll step through how to install and use Java Web Start and the Java Web Start developer pack, and how to enable your application to use Java Web Start-specific features. You'll also learn how to prepare and install your Java Web Start-enabled application on a Web server, and how to run it using a browser and the Java Web Start browser plug-in.
A Sample Java Web Start App
I use a very simple application in this article because I'm more interested in how it fits into the Java Web Start system than in the application itself. Figure 1 shows the sample application, called Thingy. Although it doesn't do much—click inside the window and you can move the vortex around—I've added a bonus feature that enables Thingy to print an image of itself using the Java Web Start runtime. This feature will help you learn how an application interacts with the Java Web Start runtime. (See Listing 1 for the full source code.)
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The Java Web Start Developer Pack 
The Java Web Start Architecture 
Creating the JAR File
