--- /home/matt/mc-dev-private//net/minecraft/server/EnchantmentThorns.java	2015-02-26 22:40:22.463608141 +0000
+++ src/main/java/net/minecraft/server/EnchantmentThorns.java	2015-02-26 22:40:22.463608141 +0000
@@ -29,7 +29,7 @@
         Random random = entityliving.bc();
         ItemStack itemstack = EnchantmentManager.a(Enchantment.THORNS, entityliving);
 
-        if (a(i, random)) {
+        if (entity != null && a(i, random)) { // CraftBukkit
             if (entity != null) {
                 entity.damageEntity(DamageSource.a(entityliving), (float) b(i, random));
                 entity.makeSound("damage.thorns", 0.5F, 1.0F);