I can't open .jar files properly
So, I have a few games on my mac that follows the .jar extension. I was playing them normally, but trying to open the files now, instead of popping the game screen, it uses the Archive Utility, generating another file with the extension .jar.cpgz, and I tried opening it too, only to find out that it goes back and generates a .jar file. What do I do? I have the latest version of java installed.
iMac, macOS Sierra (10.12.6)