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IcedTea-Web Usage Instructions

Validate Installation on Windows

Java 8

Make sure you have Java 8.

C:\>java -version openjdk version "1.8.0_402" OpenJDK Runtime Environment (Zulu (build 1.8.0_402-b06) OpenJDK 64-Bit Server VM (Zulu (build 25.402-b06, mixed mode)


Check that the JAVA_HOME variable has been defined and points to the correct location of the Java installation.

C:\>echo %JAVA_HOME% C:\Program Files\Zulu\zulu-8\

IcedTea-Web in PATH variable

Check that the IcedTea-Web directory has been added to a PATH variable.

C:\>echo %PATH% C:\Program Files\IcedTeaWeb\WebStart\bin;C:\Program Files\Zulu\zulu-8\bin\;C:\Windows\system32;C:\Windows;...

How to Start a WebStart application with IcedTea-Web

In modern browsers, a JNLP-file will be downloaded and saved to downloads folder, and can’t be opened in the browser.

Once a JNLP-file has been downloaded, you can start it in several ways:

  • Open the Downloads directory and double-click on the JNLP-file.

    • This will only work if there is an association between the .jnlp extension and the javaws.exe binary.

  • Start a JNLP-file from the command line:

    C:\Users\YourName\Downloads>javaws application.jnlp
  • Use the full installation path of javaws.exe:

    C:\Users\YourName\Downloads>"C:\Program Files\IcedTeaWeb\WebStart\bin\javaws.exe" application.jnlp

Additional Tools

A few other tools are provided with IcedTea-Web.

Web Control Panel

itweb-settings: allows to view and modify the settings for javaws and the browser plugin.

web control panel


policyeditor: allows end-users to quickly and easily view or edit the contents of their applet policy.

policy editor

How Iced-Tea-Web is Locating the Java Runtime

javaws.exe needs a valid Java Runtime, and it will search for this runtime in the following order, until it finds it:

  1. Check for the deployment.jre.dir property.

  2. Check the JAVA_HOME environmental variable.

  3. Check if there is an embedded Java Runtime with IcedTea-Web.

  4. Check Windows registry keys.

  5. Check if there is a Java Runtime in the PATH variable.