I had in my mod a player tick event when i running this on my test server the player will kick form the server and i get this error:

 

java.lang.NoSuchMethodError: net.minecraft.entity.player.PlayerInventory.func_70440_f(I)Lnet/minecraft/item/ItemStack;
	at net.luis.cave.events.server.entity.OnPlayerTick.PlayerTick(OnPlayerTick.java:27)
	at net.minecraftforge.eventbus.ASMEventHandler_19_OnPlayerTick_PlayerTick_PlayerTickEvent.invoke(.dynamic)
	at net.minecraftforge.eventbus.ASMEventHandler.invoke(ASMEventHandler.java:85)
	at net.minecraftforge.eventbus.EventBus.post(EventBus.java:297)
	at net.minecraftforge.fml.hooks.BasicEventHooks.onPlayerPreTick(BasicEventHooks.java:85)
	at net.minecraft.entity.player.PlayerEntity.func_70071_h_(PlayerEntity.java:195)
	at net.minecraft.entity.player.ServerPlayerEntity.func_71127_g(ServerPlayerEntity.java:393)
	at net.minecraft.network.play.ServerPlayNetHandler.func_73660_a(ServerPlayNetHandler.java:194)
	at net.minecraft.network.NetworkManager.func_74428_b(NetworkManager.java:226)
	at net.minecraft.network.NetworkSystem.func_151269_c(NetworkSystem.java:133)
	at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:866)
	at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:286)
	at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:788)
	at net.minecraft.server.MinecraftServer.func_240802_v_(MinecraftServer.java:643)
	at net.minecraft.server.MinecraftServer.lambda$func_240784_a_$0(MinecraftServer.java:230)
	at java.lang.Thread.run(Unknown Source)

 

and this is the tick event:

 

package net.luis.cave.events.server.entity;

import net.luis.cave.Cave;
import net.luis.cave.init.CaveEnchantment;
import net.minecraft.enchantment.EnchantmentHelper;
import net.minecraft.entity.player.ServerPlayerEntity;
import net.minecraft.util.math.BlockPos;
import net.minecraft.world.World;
import net.minecraftforge.api.distmarker.Dist;
import net.minecraftforge.event.TickEvent;
import net.minecraftforge.eventbus.api.SubscribeEvent;
import net.minecraftforge.fml.common.Mod;

@Mod.EventBusSubscriber(modid=Cave.Mod_Id, bus = Mod.EventBusSubscriber.Bus.FORGE, value = Dist.DEDICATED_SERVER)
public class OnPlayerTick {

	@SubscribeEvent
	public static void PlayerTick(TickEvent.PlayerTickEvent event) {

		ServerPlayerEntity player = (ServerPlayerEntity) event.player;
		World world = player.getEntityWorld();
		BlockPos pos = new BlockPos(player.getPosX(), player.getPosY() - 1, player.getPosZ());
		
		if (player instanceof ServerPlayerEntity) {
			
			if (EnchantmentHelper.getEnchantmentLevel(CaveEnchantment.ELYTRA_FALLING.get(), player.inventory.armorItemInSlot(2)) == 1) {
				
				player.fallDistance = 0f;
				
			}
			
			if (EnchantmentHelper.getEnchantmentLevel(CaveEnchantment.VOID_WALKER.get(), player.inventory.armorItemInSlot(0)) == 1) {
				
				if (!player.isSneaking()) {
			
					if (!world.getBlockState(pos).isSolid()) {
						
						if (player.getMotion().getY() < 0) {
							
							player.setMotion(player.getMotion().getX(), 0, player.getMotion().getZ());
							
						}
						
					}
				}
				
			}
			
		}
		
	}

}

 

ServerPlayerEntity player = (ServerPlayerEntity) event.player; // you first cast player to ServerPlayerEntity
		World world = player.getEntityWorld();
		BlockPos pos = new BlockPos(player.getPosX(), player.getPosY() - 1, player.getPosZ());
		
		if (player instanceof ServerPlayerEntity) // and here check if the player is a instance of ServerPlayerEntity thats wrong