When try to I open a .jar I get "The java JAR file could not be opened"

This is the popup I get please help

Found this error:Could not find or load main class E Caused by: java.lang.ClassNotFoundException: E

I am trying to install Forge so I can load mods for Minecraft.


Those jar files are not executed by double-clicking. You have to place it in .minecraft/versions folder and run it from launcher I think.