Java Web Start should work in any browser. The only requirement is that Java is installed properly and that the application/x-java-jnlp-file MIME type is registered in your OS.

• https://docs.oracle.com/javase/8/docs/technotes/guides/javaws/

Can you post a link to a publicly accessible page (i.e. no authentication or signing on required) where such a Java web start link is present and not working?

A Java Web Start JNLP file is basically a XML file that the server sends as application/x-java-jnlp-file and that is opened by the default application for this MIME type (Java Web Start).

Examples:

• https://docs.oracle.com/javase/tutorial/uiswing/examples/misc/index.html

Cor-el, Thank you for the help. Unfortunately, I do not have any publicly accessible sites that use the Java web start feature. The apps I use are for work and they come from storage vendors like Hitachi and Brocade.

But, I did check my mimeTypes.rdf file (in my profile dir) and it does have an entry for jnlp. So, I am perplexed as to why it is not working.

To fix the issue, I simply clicked on the link that produces the "I do not know what to do with this file" popup from Firefox. I selected the "Use a different app" feature and browsed to the path:

C:\ProgramData\Oracle\Java\javapath\javaws.exe

Problem mostly solved. Now my apps open like they should.

The only small problem is that FF used to delete the downloaded *.do file afterwards automatically. Now I have to clean them out from my downloads. It would be nice to have my cake and eat it too, but, I will take this win.

The mimeTypes.rdf file is no longer used and has been replaced by handlers.json, but I don't think that this file would store this information.

Is JWS enabled in the Java Control Center?

You can check the Windows Registry to see if the involved MIME type is set correctly since that determines what action should be taken

• application/x-java-jnlp-file
• HKEY_CLASSES_ROOT\MIME\Database\Content Type\

There is a java MIME type in my handlers.json file;

• "application/x-java-jnlp-file":{"action":4,"extensions":["jnlp"]}"

I could try to manually create an entry in the handlers.json file but I do no know enough about the syntax and actions.

I also checked the registry and I do not have an entry for

• HKEY_CLASSES_ROOT\MIME\Database\Content Type\application\x-java-jnlp-file

How would I create an entry? I cannot manually create one in the registry since I do not know the corresponding CLSID.

Thanks for the help.