File association to javaws does not work

This is on Windows 10 platform. We associate .jsp files to 'javaws' program from under java installation. This used to work fine, with javaws launched to process the contents of the JSP file. This is now broken for some users while it works OK for others. So it is specific to users' machines.

If the JSP files are associated with another program like 'notepad', it works fine with notepad launched displaying the contents of the JSP file. So it would appear it is just the javaws. It is not just JSP files, it does not work with any other file types.

The program launches fine from the command line

javaws test.jsp

It is just that the program does not launch via file association even when the association itself seems to be successful. Reinstalling Java does not help.

What could be causing this? Is there a way to debug this?