diff --git a/java/pom.xml b/java/pom.xml
index beec5034..aa3e3ce7 100755
--- a/java/pom.xml
+++ b/java/pom.xml
@@ -3,7 +3,7 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>org.msgpack</groupId>
   <artifactId>msgpack</artifactId>
-  <version>0.4</version>
+  <version>0.4.0-devel</version>
   <description>MessagePack for Java</description>
 
   <name>MessagePack for Java</name>
diff --git a/java/src/main/java/org/msgpack/template/OptionalTemplate.java b/java/src/main/java/org/msgpack/template/OptionalTemplate.java
new file mode 100644
index 00000000..6be16c1a
--- /dev/null
+++ b/java/src/main/java/org/msgpack/template/OptionalTemplate.java
@@ -0,0 +1,52 @@
+//
+// MessagePack for Java
+//
+// Copyright (C) 2009-2010 FURUHASHI Sadayuki
+//
+//    Licensed under the Apache License, Version 2.0 (the "License");
+//    you may not use this file except in compliance with the License.
+//    You may obtain a copy of the License at
+//
+//        http://www.apache.org/licenses/LICENSE-2.0
+//
+//    Unless required by applicable law or agreed to in writing, software
+//    distributed under the License is distributed on an "AS IS" BASIS,
+//    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//    See the License for the specific language governing permissions and
+//    limitations under the License.
+//
+package org.msgpack.template;
+
+import java.util.List;
+import java.util.ArrayList;
+import java.io.IOException;
+import org.msgpack.*;
+
+public class OptionalTemplate implements Template {
+	private Template elementTemplate;
+	private Object defaultObject;
+
+	public OptionalTemplate(Template elementTemplate) {
+		this(elementTemplate, null);
+	}
+
+	public OptionalTemplate(Template elementTemplate, Object defaultObject) {
+		this.elementTemplate = elementTemplate;
+		this.defaultObject = defaultObject;
+	}
+
+	public Object unpack(Unpacker pac) throws IOException, MessageTypeException {
+		if(pac.tryUnpackNull()) {
+			return defaultObject;
+		}
+		return elementTemplate.unpack(pac);
+	}
+
+	public Object convert(MessagePackObject from) throws MessageTypeException {
+		if(from.isNil()) {
+			return defaultObject;
+		}
+		return elementTemplate.convert(from);
+	}
+}
+