zoho books api: list items not working - java - zohobooks

Question

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"}
How does API work
HTTP verbs are used to access the resources - GET, POST, PUT and DELETE. All parameters in the request should be form-urlencoded. For all the APIs you need to pass authtoken and organization_id. Input JSON string should be passed using JSONString parameter.
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);
}

Answer 1

You need to pass all parameter as url parameter instead of writing in the stream. I have modified your code:
private void testZoho()
{
HttpURLConnection httpcon;
String url = "https://books.zoho.com/api/v3/items?authtoken=xxxx&organization_id=xxx&sort_column=name";
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();
//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);
}