Java Web Start

Java Web Start (JWS) is the Oracle Corporation technology used to launch rich client (Swing, Java-FX, AWT, SWT..) desktop applications directly from a network or internet link. It offers 'one click' installation for platforms that support Java.

With JDK 9 JWS is deprecated and will be removed in future release!

JWS provides many appealing features including, but not limited to, splash screens, desktop integration, file associations, automatic update (including lazy downloads and programmatic control of updates), partitioning of natives & other resource downloads by platform, architecture or locale, configuration of run-time environment (minimum J2SE version, run-time options, RAM etc.), easy management of common resources using extensions..

By default, an applet-like security sand-box is applied to code launched using JWS. To relax this sand-box the code needs to be digitally signed by the provider, and trusted by the end user. Any application launched using JWS also has access to the JNLP API. The JNLP API provides services for sand-boxed applications to achieve functionality (such as printing, opening a browser or accessing the local disks) that is normally reserved for trusted applications.

JWS applications have three security levels. The first (sand-boxed) and third (all-permissions) are equivalent to the applet sand-boxed and trusted modes. The one in between is (the oddly named) j2ee-application-client-permissions. This security level provides some services unprompted, while still placing many limits on the application.

JWS was first offered as a separate download on 14 March 2001 over two years after the release of Java 1.2, and could launch both applications and applets as free floating entities. The functionality became co-bundled with J2SE 1.4.2. Since 1.6.0_10 (the Next Generation Java Plug-In), JWS can also be used to configure applets that remain embedded in a web page.

See also:

• What is Java Web Start and how is it launched? Explanation at java.com intended for end users. Also a good description for developers who are unaware of JWS.
• Java Web Start at Oracle - The official developer homepage for JWS.
• The Java Web Start lesson in the tutorial.
• Java Web Start Technology - Overview Goes into the details of JWS deployment.
• Java Web Start Developer Guide. The Oracle guide for deploying rich client apps. using JWS.
• Java Web Start version 6 - Frequently Asked Questions (FAQ). If you have a question about JWS, this is a good place to start looking for an answer.
• Deploying Software with JNLP and Java Web Start. An older technical article by John Zukowski. Most of the links are broken or outdated, but still an informative article.
• Re-spin Your Desktop Application Into A Java Web Start Application. A video overview of converting an app. for JWS launch.
• Java Rich Internet Applications Deployment Advice. Describes the deployJava.js script designed to ensure a suitable minimum version of Java is installed before providing a link to a JWS app. or launching an applet.
• JaNeLA The Java Network Launch Analyzer is a free-ware tool created by developers to provide validation of launch files and sanity checking on many other aspects of a JWS launch.
• Java Applet & Web Start—Code Signing and the related security prompts.
• JAR File Manifest Attributes for Security.