code: public static Map<String,Object> toMetaDatas(String contentType, String fileName){
          Map<String,Object> metadatas = new HashMap<String, Object>();
          putMetaDatas(metadatas, contentType, fileName);
          return metadatas;
      }
docs: Returns a multipart metadata map
  @param contentType multipart content-type. can be null or empty
  @param fileName multipart file name. can be null or empty