Deploying a Java Web Start Application

You can deploy Java Web Start applications by using the createWebStartLaunchButton function of the Deployment Toolkit script. Java Web Start applications are launched using Java Network Launch Protocol (JNLP) The createWebStartLaunchButton function generates a link (HTML anchor tag - <a>) to the Java Web Start application's JNLP file.

This generated anchor tag is the Java Web Start application's Launch button button. When the end user clicks the Launch button, the Deployment Toolkit script ensures that the appropriate Java Runtime Environment (JRE) software is installed and then launches the Java Web Start application.

Note: Depending on the type of browser, you might be unable to view the HTML generated by the Deployment Toolkit script when you try to view the source for the web page. To view the generated HTML, try saving the HTML page after it has been loaded, or use a tool such as Firebug (a Mozilla Firefox add-on).

Note: If the client does not have the required minimum version of the JRE software, the Deployment Toolkit script redirects the browser to to allow users to download the latest JRE software.

Function signature: createWebStartLaunchButton: function(jnlp, minimumVersion) or createWebStartLaunchButton: function(jnlp)


  • jnlp – The URL of the JNLP file containing deployment information for the Java Web Start application. This URL should be an absolute path.
  • minimumVersion – The minimum version of JRE software required to run this application


  • Specifying a minimum version of JRE software that is required to run the application
    <script src=""></script>
        var url = "";
        deployJava.createWebStartLaunchButton(url, '1.6.0');
  • Enabling Java Web Start application to run on any JRE software version

    Use the createWebStartLaunchButton: function(jnlp) function if your application does not have a minimum JRE software version requirement.

Note: When deploying by using any of the previously described createWebStartLaunchButton functions, you must specify an absolute codebase in the Java Web Start application's JNLP file. This enables the Java Web Start application to be launched from the command line with the javaws <path/to/local JNLP file> command.