Try to fix a null pointer

Addresses #665

src/main/java/com/comphenix/protocol/async/AsyncFilterManager.java

@@ -318,12 +318,12 @@ public class AsyncFilterManager implements AsynchronousManager {
 
 		// The player is only be null when they're logged out,
 		// so this should be a pretty safe check
-		Player player = newEvent.getPlayer();
+		Player player = syncPacket.getPlayer();
 		if (player != null) {
 			// Start the process
 			getSendingQueue(syncPacket).enqueue(newEvent);
 
-			// We know this is occuring on the main thread, so pass TRUE
+			// We know this is occurring on the main thread, so pass TRUE
 			getProcessingQueue(syncPacket).enqueue(newEvent, true);
 		}
 	}

src/main/java/com/comphenix/protocol/concurrency/ConcurrentPlayerMap.java

@@ -3,6 +3,7 @@ package com.comphenix.protocol.concurrency;
 import com.comphenix.protocol.utility.SafeCacheBuilder;
 import com.comphenix.protocol.utility.Util;
 import com.google.common.base.Function;
+import com.google.common.base.Preconditions;
 import com.google.common.cache.CacheLoader;
 import com.google.common.cache.RemovalListener;
 import com.google.common.collect.AbstractIterator;
@@ -188,6 +189,8 @@ public class ConcurrentPlayerMap<TValue> extends AbstractMap<Player, TValue> imp
 	 * @return The key.
 	 */
 	private Object cachePlayerKey(Player player) {
+		Preconditions.checkNotNull(player, "player cannot be null");
+
 		Object key = keyMethod.apply(player);
 		
 		keyLookup.put(key, player);

src/main/java/com/comphenix/protocol/events/PacketEvent.java

@@ -50,7 +50,7 @@ public class PacketEvent extends EventObject implements Cancellable {
 			"Plugin %s changed packet type from %s to %s in packet listener. This is confusing for other plugins! (Not an error, though!)");
 	
 	private static final SetMultimap<PacketType, PacketType> CHANGE_WARNINGS =
-			Multimaps.synchronizedSetMultimap(HashMultimap.<PacketType, PacketType>create());
+			Multimaps.synchronizedSetMultimap(HashMultimap.create());
 	
 	/**
 	 * Automatically generated by Eclipse.
@@ -58,7 +58,6 @@ public class PacketEvent extends EventObject implements Cancellable {
 	private static final long serialVersionUID = -5360289379097430620L;
 	
 	private transient WeakReference<Player> playerReference;
-	private transient Player offlinePlayer;
 
 	private PacketContainer packet;
 	private boolean serverPacket;
@@ -90,7 +89,7 @@ public class PacketEvent extends EventObject implements Cancellable {
 	private PacketEvent(Object source, PacketContainer packet, NetworkMarker marker, Player player, boolean serverPacket, boolean filtered) {
 		super(source);
 		this.packet = packet;
-		this.playerReference = new WeakReference<Player>(player);
+		this.playerReference = new WeakReference<>(player);
 		this.networkMarker = marker;
 		this.serverPacket = serverPacket;
 		this.filtered = filtered;
@@ -99,7 +98,7 @@ public class PacketEvent extends EventObject implements Cancellable {
 	private PacketEvent(PacketEvent origial, AsyncMarker asyncMarker) {
 		super(origial.source);
 		this.packet = origial.packet;
-		this.playerReference = origial.playerReference;
+		this.playerReference = origial.getPlayerReference();
 		this.cancel = origial.cancel;
 		this.serverPacket = origial.serverPacket;
 		this.filtered = origial.filtered;
@@ -317,24 +316,26 @@ public class PacketEvent extends EventObject implements Cancellable {
 		this.cancel = cancel;
 	}
 
-	/**
+	private WeakReference<Player> getPlayerReference() {
-	 * Retrieves the player that has sent the packet or is recieving it.
-	 * @return The player associated with this event.
-	 */
-	public Player getPlayer() {
 		Player player = playerReference.get();
 
-		// Check if the player has been updated so we can do more stuff
 		if (player instanceof TemporaryPlayer) {
 			Player updated = player.getPlayer();
 			if (updated != null && !(updated instanceof TemporaryPlayer)) {
 				playerReference.clear();
 				playerReference = new WeakReference<>(updated);
-				return updated;
 			}
 		}
 
-		return player;
+		return playerReference;
+	}
+
+	/**
+	 * Retrieves the player that has sent the packet or is receiving it.
+	 * @return The player associated with this event.
+	 */
+	public Player getPlayer() {
+		return getPlayerReference().get();
 	}
 
 	/**
@@ -467,7 +468,8 @@ public class PacketEvent extends EventObject implements Cancellable {
 		output.defaultWriteObject();
 
 		// Write the name of the player (or NULL if it's not set)
-		output.writeObject(playerReference.get() != null ? new SerializedOfflinePlayer(playerReference.get()) : null);
+		Player player = getPlayer();
+		output.writeObject(player != null ? new SerializedOfflinePlayer(player) : null);
 	}
 
 	private void readObject(ObjectInputStream input) throws ClassNotFoundException, IOException {
@@ -479,8 +481,8 @@ public class PacketEvent extends EventObject implements Cancellable {
 		// Better than nothing
 	    if (serialized != null) {
 	    	// Store it, to prevent weak reference from cleaning up the reference
-	    	offlinePlayer = serialized.getPlayer();
+		    Player offlinePlayer = serialized.getPlayer();
-	    	playerReference = new WeakReference<Player>(offlinePlayer);
+	    	playerReference = new WeakReference<>(offlinePlayer);
 	    }
 	}