Serializing HashMap By MessagePack for Java.

gistfile1.txt

@Test
public void testSerliazingMapByMessagePack(){
    Map<String, Object> map = new HashMap<String, Object>();
    map.put("int", 1);
    map.put("long", 1L);
    map.put("date", new Date());
    map.put("string", "test");

    byte[] buffer = MessagePack.pack(map);
    for (byte b : buffer) {
	      System.out.print(Integer.toHexString(b & 0xFF) + " ");
    }
    System.out.println();
    System.out.println("buffer.length: " + buffer.length);
    System.out.println();
    
    InputStream in = new ByteArrayInputStream(buffer);
    Unpacker unpacker = new Unpacker(in);
    
    for(Object obj : unpacker){
    	MapType mapType = (MapType)obj;
    	Map<MessagePackObject, MessagePackObject> ret = mapType.asMap();
    	for(MessagePackObject key : ret.keySet()){
    	    String keyStr = key.asString();
    	    Object value = ret.get(key);
    	    System.out.println(String.format("%s: %s", keyStr, value));
    	}
    }
}

Which msgpack version are you using ? @masayuki038