public String doGetRequest (String operation) {    
    try {      
      URL url = new URL(dexmaApiURL+operation);
      HttpURLConnection conn = (HttpURLConnection) url.openConnection();
      conn.setRequestMethod("GET");
      conn.setRequestProperty("Accept", "application/json");
      conn.addRequestProperty("x-dexcell-token", token);
   
      if (conn.getResponseCode() != 200) {
        throw new RuntimeException("Failed : HTTP error code : "
            + conn.getResponseCode());
      }     
       
      String response = IOUtils.toString(conn.getInputStream(), "UTF-8");
      //DEBUG
      //System.out.println("Response for operation "+operation+" : "+response);
      conn.disconnect();      
      return response;
   
      } catch (MalformedURLException e) {
        //Shouldn't get here!   
        e.printStackTrace();
        throw new RuntimeException("Review code at operation: '"+operation+"'");
        
      } catch (IOException e) {
        e.printStackTrace();
        throw new RuntimeException("IOException: '"+e.getMessage()+"'");
      }   
  }