Reactivate Java Webstart in Mac OS X

Since an update on Mac OS X 10.5 (Leopard) Apple disabled Java’s Webstart functionality. That has not changed till now (Mac OS X 10.8, Mountain Lion). But if you need this function this how-to describes how to reactivate Webstart.

Apple provided an own how-to regarding this problem at Java for OS X 2014-001.

Background

Because Java had some serious security issues, Apple decided to deactivate not only Java Applets but also Webstart.

After a click of a Webstart link the following error message appears (in Firefox):

No Java runtime present, requesting install. Unable to locate a Java Runtime to invoke.

The symbolic link javaws in /usr/bin points to /System/Library/Frameworks/JavaVM.framework/Versions/A/Commands/javaws. This version does not work.

The working version is located in /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home/bin/javaws.

Solution

To link javaws to the working version, you have to follow the instructions below:

1. Login as an user with administration privileges.
2. Open a Terminal Window.
3. Delete the old link in /usr/bin by typing:

   sudo rm /usr/bin/javaws

   in the Terminal followed by pressing enter.

4. After entering the password the last step is setting a symbolic link to the right javaws version:

   sudo link /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home/bin/javaws /usr/bin/javaws

5. Now, a click on a Webstart link opens a message box (in Firefox) which asks you if you really want to open this Webstart application. Proceed by click on “open” and you succeeded. The jnlp file is always downloaded and stored in the Dowloads folder after clicking on the Webstart-Link.

If you want to start the Webstart-App later offline you just need to enter the following line in a terminal window (replace “webstartapp.jnlp” with the appropriate file name):

javaws ~/Downloads/webstartapp.jnlp

Issues with Safari

As already mentioned, there are issues with the Safari browser. When you click on a Webstart link, Safari starts downloading but breaks up after a few seconds without any error messages. No jnlp file is downloaded. Till now I have not find a solution for Safari. With Firefox and Chrome Webstart works as expected.