--- a/src/main/java/alice/jungle/persistent/PersistentJournal.java	Fri Dec 20 06:51:35 2013 +0900
+++ b/src/main/java/alice/jungle/persistent/PersistentJournal.java	Fri Dec 20 20:47:35 2013 +0900
@@ -18,10 +18,14 @@
 	
 	private static ChangeListWriter WRITER;
 	private static ChangeListReader READER;
-	private static MessagePack msgpack = new MessagePack();
+	private static MessagePack msgpack;
 	private static OutputStream out = null;
 	private static InputStream in = null;
 	
+	static {
+		msgpack = new MessagePack();
+	}
+	
 	public PersistentJournal() {
 	}
 	
@@ -73,7 +77,7 @@
 		return in;
 	}
 	
-	public static MessagePack getMessagePack() {
+	public static MessagePack getMsgPackInstance() {
 		return msgpack;
 	}