I have seen another question on this topic, but I am unable to find the folder that the apparent solution to the problem. I am running (I think) macOS Sierra 10.12.2. The problem only started a few days ago, before that everything worked fine. Everytime I try to open a .jar file it duplicates it with the ending .cpgz
iMac, iOS 10.2
Open or Run?
If the latter, Jar Launcher is not installed by default, so any attempts to open a .jar will just expand it as it is a compressed folder.
The only way to get the Jar Launcher program is to install a Java Development Kit, JDK.
It may require the installation of Apple's Java 6.
If you installed a java version from Java.com, it does not install the Jar Launcher, but you could run the .jar using the java executable embedded in the web applet plugin that is in the /Library/Internet Plug-Ins folder via the Terminal.
A Jar is essentially a program--really a Java Archive. However, that is how java programs can be distributed.
Do you want to Run the program in the Jar, or do you want to see the bits and pieces of the program? Sounds like you want to run it which I explained earlier.
Thank you, this did stop the duplicating, however it just makes the file into a bunch of little pieces instead of opening it
How to get Mac to open .jar files without duplicating them?
