Forge 1.12.2 installer won't launch

[The Wet One]

I chose open with because it wasn't opening with java, and so I navigated to the java executable and now the Forge installer won't launch.I've tried getting rid of Java, and the installer completely, but it still won't work.

[LexManos]

Some zip managers like to take control of the .jar file extension away from Java.
Make sure you have Java installed and try running Jarfix once, then try the installer again.