Board Thread:Bug Reports/@comment-29723156-20160828115556/@comment-27509628-20170414161827

Sinthorion wrote: The System.exit warning looks like it is caused by something else, not this mod.

I know this is old, but System.exit is a warning the comes bundled with forge, you'll always get it. It's nothing to worry about, Minecraft uses System.exit, and forge thinks it's a mod that calls it. For a mod, you should never call System.exit, as it shuts down the game without saving anything.