package com.mongoproject;

import com.mongodb.*;

import javax.management.Query;
import java.net.UnknownHostException;
import java.nio.ByteBuffer;
import java.nio.charset.Charset;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import java.util.UUID;
import com.mongoproject.ByteArrayWrapper;
import org.bson.types.ObjectId;

// Created by Sasanka on 27-Aug-2014.
public class MongoBinary2 {

    public static void main(String arg[]) throws UnknownHostException {

        MongoClient mongoClient = new MongoClient( "localhost" , 27017 );
        DB db = mongoClient.getDB("chat");
        DBCollection coll = db.getCollection("test");
        byte[] uuid = "uuid".getBytes();

        DBCursor cursor =null;
        coll.save(new BasicDBObject("_id", uuid));


        byte[] findUuid = "uuid".getBytes();

        BasicDBObject query = new BasicDBObject("_id", findUuid);

        cursor = coll.find(query);
        while(cursor.hasNext()){

            BasicDBObject dbObject = (BasicDBObject)cursor.next();
            byte[] retrieved = (byte[])dbObject.get("_id");
            System.out.println(new String(retrieved));
        }

    }


}


Output : uuid