the method public boolean matches(InventoryCrafting inv, World world);

the exception on this method is always thrown, also has a big impact on performance, it took me a second while I try to craft something (at least when I'm using with other mods)

Also
I don't understand what really does this method, only puts two fields as accesible, every time (and the try always is failing in line 37.

and the for it is doing anything but iterate on a foor loop.

This is on the 6.1 branch - which is by nature extremely experimental. I commented said code for now, but it's not surprising that very wrong things happen there.