What is JavaWS (Java Web Start)?

JavaWS (Java Web Start) is an application-deployment technology that gives you the power to launch full-featured applications with a single click from your Web browser. You can now download and launch applications, such as a complete spreadsheet program or an Internet chat client, without going through complicated installation procedures.

Java Web Start includes the security features of the Java platform, so the integrity of your data and files is never compromised. In addition, Java Web Start technology enables you to use the latest Java SE technology with any browser.

With Java Web Start, you launch applications simply by clicking on a Web page link. If the application is not present on your computer, Java Web Start automatically downloads all necessary files. It then caches the files on your computer so the application is always ready to be relaunched anytime you want—either from an icon on your desktop or from the browser link. And no matter which method you use to launch the application, the most current version of the application is always presented to you.

The technology underlying Java Web Start is the Java Network Launching Protocol (JNLP). Java Web Start is a JNLP client and it reads and parses a JNLP descriptor file (JNLP file). Based on the JNLP descriptor, it downloads appropriate pieces of a client application and any of its dependencies. If any of the pieces of the application are already cached on the client machine, then those components are not downloaded again, unless they have been updated on the server machine. After you download and cache the client application, JWS launches it natively on the client machine.

The diagram below is the JavaWS (Java Web Start) architecture for deploying Java applications over the Internet:

⇒ What Is JNLP (Java Network Launching Protocol)

⇐ Introduction of JavaWS and JNLP

⇑ Introduction of JavaWS and JNLP

⇑⇑ FAQ for JavaWS (Java Web Start)