https://github.com/MinecraftForge/MinecraftForge/blob/1.8.8/src/main/java/net/minecraftforge/fml/common/gameevent/TickEvent.java#L50
event.entity does not exist
@EventBusSubscriber tells forge "hey this is a class that has event methods"
@SubscribeEvent tells forge "hey this method needs to recessive the event"
you need @SubscribeEvent on the event methods
https://github.com/loordgek/Extragenarators/blob/trytofix/src/main/java/loordgek/extragenarators/event/CommonEventHandler.java#L14
https://github.com/Excaliburns/ModPractice/blob/master/src/main/java/network/tutmodHuskItemMessage.java#L127
a itemstack can not be null, check for ItemStack.isEmpty
https://gist.github.com/loordgek/bb6b9822d9ddadac09ac9af6e5c96de0 fixed
if you are asking "why are you adding a IItehandler tot the player"
https://github.com/MinecraftForge/MinecraftForge/issues/3344