Add some debug info for #202

Also /really/ make sure it's only called once

modules/API/src/main/java/com/comphenix/protocol/ProtocolLogger.java

@@ -32,6 +32,10 @@ public class ProtocolLogger {
 		ProtocolLogger.logger = plugin.getLogger();
 	}
 
+	private static boolean isDebugEnabled() {
+		return ProtocolLibrary.getConfig().isDebug();
+	}
+
 	/**
 	 * Logs a message to console with a given level.
 	 * @param level Logging level
@@ -60,4 +64,10 @@ public class ProtocolLogger {
 	public static void log(Level level, String message, Throwable ex) {
 		logger.log(level, message, ex);
 	}
+
+	public static void debug(String message, Object... args) {
+		if (isDebugEnabled()) {
+			log("[Debug] " + message, args);
+		}
+	}
 }

modules/API/src/main/java/com/comphenix/protocol/injector/netty/NettyProtocolRegistry.java

@@ -20,6 +20,7 @@ import java.util.Map;
 import java.util.Map.Entry;
 
 import com.comphenix.protocol.PacketType;
+import com.comphenix.protocol.ProtocolLogger;
 import com.comphenix.protocol.PacketType.Protocol;
 import com.comphenix.protocol.PacketType.Sender;
 import com.comphenix.protocol.injector.netty.ProtocolRegistry;
@@ -39,6 +40,8 @@ public class NettyProtocolRegistry extends ProtocolRegistry {
 
 	@Override
 	protected synchronized void initialize() {
+		ProtocolLogger.debug("NettyProtocolRegistry#initialize()"); // Debug for issue #202
+
 		Object[] protocols = enumProtocol.getEnumConstants();
 
 		// ID to Packet class maps

modules/API/src/main/java/com/comphenix/protocol/injector/packet/PacketRegistry.java

@@ -55,17 +55,16 @@ public class PacketRegistry {
 	private static boolean INITIALIZED;
 
 	/**
-	 * Initialize the packet registry.
+	 * Initializes the packet registry.
 	 */
 	private static void initialize() {
 		if (INITIALIZED) {
-			// Make sure they were initialized
-			if (NETTY == null)
-				throw new IllegalStateException("No initialized registry.");
-			return;
+			if (NETTY == null) {
+				throw new IllegalStateException("Failed to initialize packet registry.");
+			}
 		}
 
-		// Check for netty
+		INITIALIZED = true;
 		NETTY = new NettyProtocolRegistry();
 	}