Icedtea-web ~ jnlp launcher



As replacement for Java Web Start, IcedTea-web, provides a Java Web browser plugin. What I like about this project is that it is so clean, easy to access, easy to execute some Java Network Launch Protocol files.


Control Panel


Iced Tea Web – Control Panel

JVM Settings

Using this setting will help to set the JVM properties.

Policy Settings

This basically is a link to the java.policy:

[$JAVA_HOME/jdk1.8.0_191]$ cd jre/lib/security/
[fdemeloj@fdemeloj security]$ ls
blacklist blacklisted.certs cacerts java.policy javaws.policy policy trusted.libraries

         Extended applet security

So here one can add the exceptions, in a similar way to JWS. So then you edit the rows in order to add the site exception.

IcedTea-Web Tests/Samples

On the link you can select the test to be done, the tests are .jnlp files that you execute directly clicking on it (of course, the default will be IcedTea-web) so we open. This one is pretty cool: circuit-construction-kit-dc_en.jnlp – Developed by PhET at the University of Colorado.


IcedTea test – circuit construction

The code is pretty straightforward, is jnlp file:

You will have a XML file with:

                    1. code base link (to fetch),

                    2.a jar file (to execute),

                    3. some properties – language for example

<?xml version=”1.0″ encoding=”utf-8″?>

<!– JNLP File for Circuit Construction Kit (DC Only) –>

<jnlp spec=”1.0+” codebase=”” href=”circuit-construction-kit-dc_en.jnlp”>

<property name=”javaws.phet.locale” value=”en” />
<property name=”javaws.user.language” value=”en” />

<jar href=”circuit-construction-kit_all.jar”/> ii


<application-desc main-class=”edu.colorado.phet.circuitconstructionkit.CircuitConstructionKitDCApplication“>



  1. The main class to be executed is set with <application-desc main-class>
  2. Interestingly they have this application for several languages, including Korean and Portuguese! It is possible to change the language by changing the property <property name=”javaws.phet.locale” value=”LANGUAGE” /> AND the doc circuit-construction-kit-dc_es.jnlp. And yes, Ampolleta means light in Spanish.

The tags and meaning of them can be found in JNLP Syntax



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