Paper/src/main/java/net/minecraft/server/EntityCow.java

package net.minecraft.server;

// CraftBukkit start
import java.util.List;

import org.bukkit.Location;
import org.bukkit.craftbukkit.event.CraftEventFactory;
import org.bukkit.craftbukkit.inventory.CraftItemStack;
import org.bukkit.event.player.PlayerBucketFillEvent;
// CraftBukkit end

public class EntityCow extends EntityAnimal {

    public EntityCow(World world) {
        super(world);
        this.texture = "/mob/cow.png";
        this.b(0.9F, 1.3F);
    }

    public int getMaxHealth() {
        return 10;
    }

    public void b(NBTTagCompound nbttagcompound) {
        super.b(nbttagcompound);
    }

    public void a(NBTTagCompound nbttagcompound) {
        super.a(nbttagcompound);
    }

    protected String c_() {
        return "mob.cow";
    }

    protected String m() {
        return "mob.cowhurt";
    }

    protected String n() {
        return "mob.cowhurt";
    }

    protected float o() {
        return 0.4F;
    }

    protected int getLootId() {
        return Item.LEATHER.id;
    }

    protected void dropDeathLoot(boolean flag, int i) {
        // CraftBukkit start - whole method
        List<org.bukkit.inventory.ItemStack> loot = new java.util.ArrayList<org.bukkit.inventory.ItemStack>();
        int j = this.random.nextInt(3) + this.random.nextInt(1 + i);

        if (j > 0) {
            loot.add(new org.bukkit.inventory.ItemStack(Item.LEATHER.id, j));
        }

        j = this.random.nextInt(3) + 1 + this.random.nextInt(1 + i);

        if (j > 0) {
            loot.add(new org.bukkit.inventory.ItemStack(this.isBurning() ? Item.COOKED_BEEF.id : Item.RAW_BEEF.id, j));
        }

        CraftEventFactory.callEntityDeathEvent(this, loot);
        // CraftBukkit end
    }

    public boolean b(EntityHuman entityhuman) {
        ItemStack itemstack = entityhuman.inventory.getItemInHand();

        if (itemstack != null && itemstack.id == Item.BUCKET.id) {
            // CraftBukkit start - got milk?
            Location loc = this.getBukkitEntity().getLocation();
            PlayerBucketFillEvent event = CraftEventFactory.callPlayerBucketFillEvent(entityhuman, loc.getBlockX(), loc.getBlockY(), loc.getBlockZ(), -1, itemstack, Item.MILK_BUCKET);

            if (event.isCancelled()) {
                return false;
            }

            entityhuman.inventory.setItem(entityhuman.inventory.itemInHandIndex, CraftItemStack.createNMSItemStack(event.getItemStack()));
            // CraftBukkit end

            return true;
        } else {
            return super.b(entityhuman);
        }
    }

    protected EntityAnimal createChild(EntityAnimal entityanimal) {
        return new EntityCow(this.world);
    }
}