Finally got it running using the following workaround I found:
I searched for ".jar files not opening in Windows 10"
This suggestion worked for me.
"Solution 4 – Create a .bat file
According to users, you can run jar files on Windows 10 by using this simple workaround. This solution requires you to create a .bat file and use it every time you want to run a specific jar file. The process is rather simple and you can do it by following these steps:
Locate your jar file. In the same folder, create a new Notepad file. To do that, right-click empty space in the directory and choose New > Text Document.
When Notepad opens, enter java -jar filename.jar. Be sure to replace filename.jar with the actual name of the file.
Navigate to the File > Save as.
Set Save as type to All files. Now, enter the desired name for the file. Keep in mind that you need to have .bat as an extension or else the solution won’t work. Save the file in the same location where your jar file is located.
After doing that, locate your .bat file and double-click it. Your jar file will now open. Keep in mind that you need to repeat this process for every jar file that you want to run on your PC. In addition, be sure to save the .bat file in the same location as your jar file."
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