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{{Short description|Framework for running Java apps in a web browser}}
In [[computing]], '''Java Web Start''' (also known as '''JavaWS''', '''javaws''' or '''JAWS''') is a deprecated [[Software framework|framework]] developed by [[Sun Microsystems]] (now [[Oracle Corporation|Oracle]]) that allows users to start [[application software]] for the [[Java Platform]] directly from the [[Internet]] using a [[web browser]]. The technology enables seamless version updating for globally distributed applications and greater control of memory allocation to the [[Java virtual machine]].
Java Web Start was distributed as part of the Java Platform until being removed in Java SE 11, following its deprecation in Java SE 9. The code for Java Web Start was not released by Oracle as part of [[OpenJDK]], and thus OpenJDK originally did not support it. [[IcedTea#IcedTea-Web|IcedTea-Web]] provides an independent open source implementation of Java Web Start that is currently developed by the [[AdoptOpenJDK]] community, [[RedHat]] and [[Karakun AG]], and which is bundled in some OpenJDK installers.<ref>{{Citation|title=ojdkbuild - WebStart|date=2019-04-29|url=https://github.com/ojdkbuild/ojdkbuild/wiki/WebStart/7b6f869d901b401cd2e5dd92990daad54040acd4|access-date=2019-05-31}}</ref> Next to this OpenWebStart provides an [[open source]] based implementation that is based on IcedTea-Web but offers more features and commercial support options.
== Functionality ==
Unlike [[Java applet]]s, Web Start applications do not run inside the browser. By default they run in the same [[sandbox (computer security)|sandbox]] as applets, with several minor extensions like allowing to load and save the file that is explicitly selected by the user through the file selection dialog. Only [[Digital signature|signed]] applications can be configured to have additional permissions.
Web Start can also launch unmodified applets that are packaged inside .jar files, by writing the appropriate JNLP file. This file can also pass the applet parameters. Such applets also run in a separate frame. Applet launcher may not support some specific cases like loading class as resource.
Like applets, Java Web Start is [[cross-platform]].
== Deprecation ==
With [[Java version history|JDK9]], several deployment technologies including applets and Java Web Start were deprecated by Oracle.<ref>
[http://www.oracle.com/technetwork/java/javase/9-deprecated-features-3745636.html JDK9 Release Notes]
</ref><ref>{{cite web |url=https://blogs.oracle.com/java-platform-group/moving-to-a-plugin-free-web |title=Moving to a Plugin-Free Web |date=January 27, 2016 |first=Dalibor |last= Topić }}</ref>
In March 2018, Oracle announced it will not include Java Web Start in Java SE 11 (18.9 LTS) and later. Developers will need to transition to other deployment technologies.<ref>{{Cite web|url=http://www.oracle.com/technetwork/java/javase/javaclientroadmapupdate2018mar-4414431.pdf|title=Java Client Roadmap Update|date=March 2018|quote=Oracle will not include Java Web Start in Java SE 11 (18.9 LTS) and later. Oracle will begin encouraging application developers and users to transition away from Java Web Start and encourage non-commercial consumers to remove any unused or non-supported Oracle JRE installations from their desktops.}}</ref> A few stand-alone [[#Alternatives|alternatives]] have since arisen.
== Implementation ==
[[Image:Java WebStartApplicationMan.png|thumb|250px|Early versions of Java Web Start came with an application manager where, e.g., Sun's demo applications could be launched]]
The developer prepares a special XML file with JNLP extension. This file describes the application requirements, code ___location, parameters and additional permissions (if any). The browser downloads this file as any other and (following its [[MIME type]], <code>application/x-java-jnlp-file</code>) opens it with Web Start tool. Web Start tool downloads all necessary resources and launches the application.
Java Web Start provides a series of [[Class (computer science)|class]]es in the
Sun introduced version 1.0 of Web Start in March 2001
[http://www.sun.com/smi/Press/sunflash/2001-03/sunflash.20010314.1.html Java Web Start 1.0 press release]
</ref> while 64-bit Windows support was added only in Java 6<ref name="win64">[http://bugs.sun.com/view_bug.do?bug_id=4802695 Bug ID 4802695, Support 64-bit Java Plug-in and Java webstart on Windows/Linux on AMD64]</ref> (later than 64-bit Java was first available). Since [[Java Platform, Standard Edition|J2SE]] 1.4 Web Start comes as a default part of [[Java Runtime Environment]] (JRE) called <code>javaws</code>,
== Java Network Launching Protocol (JNLP) ==
Programmers often speak of the '''Java Network Launching Protocol''' ('''JNLP''') interchangeably with the term "Web Start". The JNLP protocol, defined with an [[XML
Important Web Start features include the ability to automatically download and install a JRE in the case where the user does not have Java installed, and for programmers to specify which JRE version a given program needs in order to execute. The user does not have to remain connected to the Internet to execute the downloaded programs, because they execute from a locally maintained [[cache (computing)|cache]]. Updates of the software download from the Web and become available when the user has a connection to the Internet, thus easing the burden of deployment.
Any computer user can use JNLP simply by installing a JNLP client (most commonly Java Web Start). The installation can occur automatically such that the end-user sees the client launcher downloading and installing the Java application when first executed.
JNLP
JNLP mirrors this process; in the same way that a Web browser renders a webpage, a JNLP client "renders" a [[Java application|Java app]]. After the user clicks on a weblink, the browser submits a URL to a webserver, which replies with a JNLP file (instead of a HTML file) for the application. The JNLP client parses this file, requests the resources specified (jar files), waits for the retrieval of all required resources, and then launches the application. The JNLP file can list resources as "lazy", which informs the JNLP client that the application does not need those resources to start, but can retrieve them later on when/if the application requests them.
== Example ==
{{original research|section|date=September 2020}}
The example below gives a simple JNLP file to launch the applet, specifying code base, source, main class and window size. Such file contains all necessary references and is self-sufficient to launch the application. As no permissions are requested, the code will run in a sandbox. JNLP also states that this application can run offline (if already cached) and should be updated as a background process.
<syntaxhighlight lang='xml'>
<?xml version="1.0" encoding="UTF-8"?>
<jnlp spec="1.0+" codebase="http://ultrastudio.org/upload" href="">
<information>
<title>Launch applet with Web Start</title>
<vendor>Foo Bar Inc.</vendor>
<offline-allowed/>
</information>
<resources>
<j2se version="1.5+" href="http://java.sun.com/products/autodl/j2se"/>
<jar href="Ray-2.3-4ca60e46-0956-3f22-983c-e3ed986dfd03.jar" main="true" />
</resources>
<applet-desc name="Ray diagram applet" main-class="raydiagramsapplet.Main" width="300" height="200">
</applet-desc>
<update check="background"/>
</jnlp>
</syntaxhighlight>
== Pack200 compression ==
To reduce the size of a Java Web Start application Sun Microsystems introduced a compression system called [[Pack200]] in Java 1.5.0. It
Java Web Start has supported Pack200 since it first appeared, but initially this feature required server-side cooperation and a certain amount of expertise to set up. When
On slow connections Pack200 gives a performance boost in application startup time and download time.
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By default, Java Web Start applications run "restricted", which means that they do not have access to some system resources such as local files. But publishers can remove these restrictions by signing their Web Start applications with the <code>jarsigner</code> tool that comes with the [[Java Development Kit|JDK]].
==
{{see also|IcedTea#IcedTea-Web}}
The open-source [[IcedTea]] project provides an alternative JNLP implementation in ''IcedTea-Web''. As of version 1.7.2, it also works on newer versions without official JWS support.<ref>[https://github.com/adoptopenjdk/icedtea-web/ icedtea-web]. open source implementation of web start</ref>
To run Java Web Start-based application after the release of Java 11, the company [[Karakun AG]] has released the open source tool [[:de:OpenWebStart|OpenWebStart]], based on IcedTea-Web.<ref>{{Cite web|title=OpenWebStart|url=https://openwebstart.com/|access-date=2020-07-20|website=OpenWebStart|language=en}}</ref> The tool includes all the functionality of IcedTea-Web and adds extended features, such as native installers for Mac OS, Windows, and Linux. IcedTea-Web was created with support from [[RedHat]] and [[AdoptOpenJDK]].<ref>{{Cite web|last=hendrik|date=2019-12-10|title=How open source saved WebStart|url=https://guigarage.com/2019/12/10/webstart-advent.html|access-date=2020-07-20|website=GuiGarage|language=en}}</ref>
== Notable applications ==
{{unreferenced section|date=October 2018}}
* [[ArgoUML]] – an [[Unified Modeling Language|UML]] diagramming application.
* [[CrossFTP]] – an FTP client and server.
* [[Elluminate Live]] – a web conferencing / virtual classroom program.
* [[Ganymede (software)|Ganymede]] – a GPL-licensed network directory management system
* [[Genie Workbench]] – a set of film production automation tools.
* [[Genevestigator]], access engine to the curated bioinformatical database.
* [[Jake2]] – A Java port of Quake 2.
* [[
* [[muCommander]] A file Manager and Norton Commander clone with SSH and ftp features
* [[PoxNora]] – a [[3/4 perspective]], [[turn-based strategy]], [[collectible card game]].
* [[Wurm Online]] – a 3D Massively Multiplayer Online Fantasy Simulator.
* [[yEd]] – a graph and diagram editor.
== See also ==
{{Portal|
* [[ClickOnce]], [[Microsoft]] [[.NET Framework|.NET]]'s similar framework.
==
{{
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* [
{{Java (Sun)}}
[[Category:Java specification requests|Web Start]]
[[Category:2001
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