The Java JAR file could not be launched. On a mac

[chezpaul]

Hey everyone,

 

I'm trying to extract the files from forge-1.12.2-14.23.5.2854-universal.jar.

I've done this before, many time to create a technicpack modpack. I'm running java 8 v212 and just updated to Mac OS X Catalina 10.15.6

When I double click the  forge-1.12.2-14.23.5.2854-universal.jar file, I get an error window saying The Java JAR file "forge-1.12.2-14.23.5.2854-universal.jar" could not be launched.

So okay , this happened to me a month ago for the first time and I was able in terminal to run it by typing java -jar ~/users/user/Desktop/forge-1.12.2-14.23.5.2854-universal.jar

But now when I try it in the terminal, I get this:

 

We appear to be missing one or more essential library files.

You will need to add them to your server before FML and Forge will run successfully.java.lang.ClassNotFoundException: net.minecraft.launchwrapper.Launch

at java.net.URLClassLoader.findClass(URLClassLoader.java:382)

at java.lang.ClassLoader.loadClass(ClassLoader.java:418)

at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:355)

at java.lang.ClassLoader.loadClass(ClassLoader.java:351)

at java.lang.Class.forName0(Native Method)

at java.lang.Class.forName(Class.java:348)

at net.minecraftforge.fml.relauncher.ServerLaunchWrapper.run(ServerLaunchWrapper.java:52)

at net.minecraftforge.fml.relauncher.ServerLaunchWrapper.main(ServerLaunchWrapper.java:34)

 

I can't find anything online regarding this little problem. 

 

Would anyone know anything about this?

 

Thanks