I see you used diesieben07's tutorial. Read the replies, you'll find the SRG names. Add them to the lines following like so:
private static final Field eventHandlerField = ReflectionHelper.findField(InventoryCrafting.class, "eventHandler",
"srgEventHandlerNameGoesHere");
private static final Field containerPlayerPlayerField = ReflectionHelper.findField(ContainerPlayer.class, "thePlayer",
"sameForThePlayer");
private static final Field slotCraftingPlayerField = ReflectionHelper.findField(SlotCrafting.class, "thePlayer", andSoOn);