Shopify OAuth step 2 issue - shopify

Question

When we try to post a request for step 2 of the authentication process, we get an http 400 error when sending request to https://hamill-murazik-and-johnston6698.myshopify.com/admin/oauth/access_token
We are able to get past step 1 and we get the temp code. But when we try to post the client_id, client_secret and code, we get back the http 400 error.
Code is shown below
public static void runTest() {
// TODO Auto-generated method stub
try{
URL url = new URL("https://hamill-murazik-and-johnston6698.myshopify.com/admin/oauth/access_token");
HttpsURLConnection connection = (HttpsURLConnection) url.openConnection();
String urlParameters = URLEncoder.encode("client_id", "UTF-8") + "=" + URLEncoder.encode("<CLIENT_ID", "UTF-8");
urlParameters += "&" + URLEncoder.encode("client_secret", "UTF-8") + "=" + URLEncoder.encode("<CLIENT_SECRET", "UTF-8");
urlParameters += "&" + URLEncoder.encode("code", "UTF-8") + "=" + URLEncoder.encode("15f01c0d8b235ffb63234c1c48822432", "UTF-8");
/*connection.setDoInput(true);
connection.setDoOutput(true);
connection.setUseCaches(false);
connection.setAllowUserInteraction(false);
connection.setRequestProperty("Content-Length", Integer.toString(102454));
connection.setRequestProperty("Content-Type", "text/plain");*/
connection.setUseCaches(false);
connection.setAllowUserInteraction(false);
connection.setDoOutput(true);
connection.setRequestProperty("Content-Length", "" + Integer.toString(urlParameters.getBytes().length));
DataOutputStream wr = new DataOutputStream(connection.getOutputStream ());
wr.writeBytes(urlParameters);
wr.flush();
wr.close();
BufferedReader in = new BufferedReader(
new InputStreamReader(
connection.getInputStream()));
String decodedString;
while ((decodedString = in.readLine()) != null) {
System.out.println(decodedString);
}
in.close();
}catch(Exception e){
e.printStackTrace();
}
}

Answer 1

I'd suggest you use a real HTTP Client library such as the Apache HttpClient library. There is a good chance you are missing something in your request or encoding something incorrectly.
The library wil provide a simpler interface to work with as well, so you can just pass in things like key-value parameters for your HTTP params and it'll just work.
Also, it appears that you are appending your authorize request into your URL parameters. You need to make a POST request for that request. In your current implementation you'd have to send that in the Body, which can be awkward in plain Java.
I highly suggest using the HttpClient library, and letting us know if that helped you out.