Detect, remove and warn about null tile entities. This prevents odd server crashes, caused by unknown reasons.

CraftBukkit-Patches/0025-Detect-remove-and-warn-about-null-tile-entities.patch

@@ -0,0 +1,30 @@
+From 06871b0489590cbdd3dd4f9cdd9f02d5397c3e6e Mon Sep 17 00:00:00 2001
+From: md_5 <md_5@live.com.au>
+Date: Sun, 3 Feb 2013 09:20:19 +1100
+Subject: [PATCH] Detect, remove and warn about null tile entities.
+
+---
+ src/main/java/net/minecraft/server/World.java | 7 +++++++
+ 1 file changed, 7 insertions(+)
+
+diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
+index 262290f..cd7ad64 100644
+--- a/src/main/java/net/minecraft/server/World.java
++++ b/src/main/java/net/minecraft/server/World.java
+@@ -1302,6 +1302,13 @@ public abstract class World implements IBlockAccess {
+ 
+         while (iterator.hasNext()) {
+             TileEntity tileentity = (TileEntity) iterator.next();
++            // Spigot start
++            if (tileentity == null) {
++                getServer().getLogger().severe("Spigot has detected a null entity and has removed it, preventing a crash");
++                iterator.remove();
++                continue;
++            }
++            // Spigot end
+             // CraftBukkit start - don't tick entities in chunks queued for unload
+             ChunkProviderServer chunkProviderServer = ((WorldServer) this).chunkProviderServer;
+             if (chunkProviderServer.unloadQueue.contains(tileentity.x >> 4, tileentity.z >> 4)) {
+-- 
+1.8.1-rc2
+