code: @Deprecated
      public com.mongodb.MapReduceOutput mapReduce(String map, String reduce, String outputTarget, DBObject query) throws MongoException {
          return mapReduce(new MapReduceCommand(dbCollection, map, reduce, outputTarget, MapReduceCommand.OutputType.REPLACE, serializeFields(query)));
      }
docs: performs a map reduce operation
  Runs the command in REPLACE output mode (saves to named collection)
  
  @param map          map function in javascript code
  @param outputTarget optional - leave null if want to use temp collection
  @param reduce       reduce function in javascript code
  @param query        to match
  @return The output
  @throws MongoException If an error occurred