when I call this list Item API in zoho books:

https://www.zoho.com/invoice/api/v3/settings/items/#list-items , the response is: {"code":4,"message":"Invalid value passed for JSONString"}

    private void testZoho() {
    JSONObject JSONString = new JSONObject();

    JSONString.put("sort_column", "name");

    String urlParameters ="authtoken=xxxxxx&organization_id=xxxxx";
    urlParameters += "&JSONString=" + JSONString.toJSONString();
    System.out.println("retJson1:\n" + urlParameters);
    HttpURLConnection httpcon;  
    String url = "https://books.zoho.com/api/v3/items";
    String data = urlParameters;
    String result = null;
    try{
    //Connect
    httpcon = (HttpURLConnection) ((new URL (url).openConnection()));
    httpcon.setDoOutput(true);

    String charset = "UTF-8";
    httpcon.setRequestProperty("Accept-Charset", charset);
    httpcon.setRequestProperty("Content-Type", "application/json;charset=" + charset);
    httpcon.setRequestMethod("GET");
    httpcon.connect();

    //Write         
    OutputStream os = httpcon.getOutputStream();
    BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(os, "UTF-8"));
    writer.write(data);
    writer.close();
    os.close();

    //Read      
    BufferedReader br = new BufferedReader(new InputStreamReader(httpcon.getInputStream(),"UTF-8"));

    String line = null; 
    StringBuilder sb = new StringBuilder();         

    while ((line = br.readLine()) != null) {  
         sb.append(line); 
    }       

    br.close();  
    result = sb.toString();

    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    } 
    System.out.println("retJson1:\n" + result);

}