Java

README

Java TM Web Start

Version 1.0.1

 
Please send comments and feedback to javawebstart-feedback@sun.com.

Table of Contents

Introduction
Installation Instructions
Using Java Web Start
Release Notes

Introduction

Java Web Start is a new deployment technology for Java TM technology-based applications.  It is the plumbing between the computer and the Internet that allows the user to launch and manage applications right off the Web. Java Web Start provides easy, one-click activation of applications, and guarantees that you are always running the latest version, eliminating complicated installation or upgrade procedures.

Traditionally, distributing software across the Web, requires the user to find the installer on the Web, download the installer, locate the installer, and execute the installer. Once, the installer is executed, it prompts for installation directories and installation options such as full, typical, or minimum. This is typically a time-consuming and complicated task, and it has to be repeated for each new version of the software.

In contrast, Web-deployed applications, such as your favorite HTML-based email client and calendar,  auction sites, and so on, are a breeze to install and use. The Web browser has automated the entire process. There is no complicated download, setup, and configuration steps, and you are guaranteed to always be running the latest version.

Java Web Start provides the same benefits to full-featured applications as described above for HTML-based applications. Java Web Start is an application deployment solution for the Web. Using a full-featured application instead of an HTML-based client can have many benefits:

The trade-off is that you have to download the application the first-time. An HTML-based application has a very low first time activation cost. Typically, a Web page is brought up in a matter of seconds. A Java TM technology-based application will require download times in the order of minutes on a typical modem connection. Java Web Start caches all downloaded files locally on the computer. Thus, although the first-time activation cost is higher for applications than for HTML pages, the subsequent times you launch an application, it will be launched almost instantaneously, since all the required resources are already available locally.

On each launch, Java Web Start checks the Web server to see if a new version of the application is available, and automatically downloads and launches it. Thus, applications are automatically brought up-to-date. There is no complicated upgrade procedure.

Security

Java Web Start is built on top of the Java 2 platform, which provides a comprehensive security architecture. Applications launched with Java Web Start will, by default, run in a restricted environment ("sandbox") with limited access to files and network. Thus, launching applications using Java Web Start maintains system security and integrity.

An application can request unrestricted access to your system. In this case, Java Web Start will show a Security Warning dialog when the application is launched for the first time. The security warning will show information about the origin of the application, i.e., the vendor who developed the application. If you choose to trust the vendor, then the application will be launched. The information about the origin of the application is based on digital code signing.

Intallation Instructions

For installation instructions and system requirements for this release, please see the installation guide.

Using Java Web Start

Java Web Start allows you to launch Java technology-based application directly from the Web. An application can be launched in three different ways: The application runs the same no matter which method you choose to launch it. In particular, Java Web Start is always going to connect back to the Web server to check for an updated version of the particular application.

Launching from a Web browser

On the Java Web Start product page (http://java.sun.com/products/javawebstart), there are links to a number of applications that can be launched with a single click of a mouse. Try launching the different applications by clicking on the launch buttons. The Web browser will launch Java Web Start, which will then download, cache, and execute the given application. You will notice that the second time you launch an application, it starts much quicker since it is already present locally and does not need to be downloaded again.

Most of the demos on the page are just downloaded and executed without any user intervention. These applications run in a restricted environment, where they are prevented from accessing the local disk and network, and can be guaranteed not to install any viruses on your computer.

Some demos require extra privileges, such as access to your local hard disk. For these applications, a security dialog will pop up with information about the origin of the application based on who digitally signed the code. The application will run only if you decide to trust the vendor.

That is really all there is to using Java Web Start, but how does it work? The HTML links that launch the applications are, in fact, standard HTML links. However, instead of pointing to another Web page, they link to a special configuration file called a JNLP file. The Web browser examines the file extension and/or the MIME type of the file, and sees that it belongs to Java Web Start. It then launches Java Web Start with the downloaded JNLP file as an argument. Java Web Start shows a splash screen and proceeds with downloading, caching, and running the application as directed by the JNLP file. 

Launching from the built-in Application Manager

The Application Manager is a built-in part of Java Web Start. It lets you quickly and easily launch applications that have previously been launched by Java Web Start. It is a combination of a History menu and a Start/Programs menu for your Web deployed Java technology-based applications. The Application Manager also allows you to see additional information about an application, and go the home page of a particular application.

You launch an application from the Application Manager by double clicking on the application icon or by clicking the launch button.

Another important feature of the Application Manager is the Preferences dialog which lets you examine and modify settings used by Java Web Start. For example, this includes tabs which allow you to:

The Application Manager is launched by either clicking on the Java Web Start icon on the desktop or in the Start Menu on Windows. On Solaris/Linux, it is launched by invoking the javaws command in the Java Web Start installation directory. The Application Manager can also be launched from a Web browser. The product page (http://java.sun.com/products/javawebstart) shows an example of this.

Launching from desktop icons and the Start Menu (Windows only)

Java Web Start can automatically create shortcuts on the Windows desktop and in the Start Menu for Web deployed Java technology-based applications. By default, Java Web Start asks the second time an application is launched, if a shortcut should be created. This can be changed using the Preference panel.

Shortcuts can also be added and removed by using the Application Manager, using the Application/Create Shortcut, and using Application/Remove Shortcut menu item.

Using Java Web Start Behind a Proxy Server/Firewall

Java Web Start must be configured with the correct proxy settings in order to launch applications from outside your firewall. Java Web Start will automatically try to detect the proxy settings from the default browser on your system (IE or Netscape on Windows, and Netscape on Solaris/Linux). Java Web Start supports most web proxy auto-configuration scripts. It can detect proxy settings in almost all environments.

If the proxy setting cannot be automatically detected, then you will be prompted to specify the proxy settings the first time you use Java Web Start. Java Web Start will also prompt you for a user name and password required to access an authenticating proxy server. This user name and password will be stored for the current invocation of Java Web Start. However, at the time a newly invoked Java Virtual Machine, if accessing a secure web site, will prompt you for the user name and password since this information is stored within a Java Virtual Machine instance.

You can also use the Java Web Start Preferences panel to view or edit the proxy configuration. Launch the Application Manager, either by clicking on the icon on the desktop (Windows), or type ./javaws in the Java Web Start installation directory (Solaris/Linux), and then select Edit/Preferences.  If you are in an environment where access to the Web is through a proxy server, you are encouraged to use the Java Web Start Preferences panel to check that these are set-up correctly.

Release Notes

For a list of bug fixes and enhancements that were made for this release of Java Web Start, please refer to the release notes.
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