anchor.diff:  // MongoDB connection
   var _mongoDb;
   
  -// world Collection
  +// World Collection
   var _worldCollection;
   
   // Fortunes Collection
   var _fortuneCollection;
   
  -// world table size
  +// World table size
   const _WORLD_TABLE_SIZE = 10000;
  -// fortune table size used only for generation of data
  +// Fortune table size used only for generation of data
   const _FORTUNE_TABLE_SIZE = 100;
   
   final _RANDOM = new Random();
   
  -class fortune implements Comparable<fortune> {
  +class Fortune implements Comparable<Fortune> {
     int id;
   
     String message;
   
  -  fortune(this.id, this.message);
  -
  -  compareTo(fortune other) => message.compareTo(other.message);
  -}
  -
  -class world {
  +  Fortune(this.id, this.message);
  +
  +  compareTo(Fortune other) => message.compareTo(other.message);
  +}
  +
  +class World {
     int id;
     int randomnumber;
   
  -  world(this.id, this.randomnumber);
  +  World(this.id, this.randomnumber);
   
     toJson() => { "id": id, "randomnumber": randomnumber };
   }
  
positive.code:             return _connectionPool.connect()
                .then((connection) {
                  return connection.execute(
                        'UPDATE "world" SET "randomnumber" = @randomnumber WHERE "id" = @id;',
                        { 
                          'randomnumber': world.randomnumber,
                          'id': world.id 
  
negative.code:        var mongoConfig = yaml.loadYaml(config);
         _mongoDb = new Db("mongodb://${mongoConfig["host"]}/${mongoConfig["database"]}");
         return _mongoDb.open().then((_) {
           _worldCollection = _mongoDb.collection("World");
           _fortuneCollection = _mongoDb.collection("Fortune");
         });
       })
     ]).then((_) {
  