Não é possível recuperar dados do php mysql para a atividade do Android

    public static JSONObject getJSONfromURL(final String URL){

        JSONObject jArray = null;
        try {
            //URL = "http://emedteam-001-site1.ctempurl.com/emed/home/getdrug?letter=a";
            URLConnection conn = new URL(URL).openConnection();
            conn.addRequestProperty("Accept", "application/json");
            conn.connect();
            InputStream is = conn.getInputStream();
            BufferedReader reader = new BufferedReader(new InputStreamReader(
                is, "UTF-8"), 8);
            StringBuilder sb = new StringBuilder();
            String line = null;
            while ((line = reader.readLine()) != null) {
                sb.append(line + "\n");
            }
            is.close();

            String str = sb.toString();
            sb = null;
            jArray  = new JSONObject(str);                          
        } catch (Exception e) {
            e.printStackTrace();
        }
        return jArray;  
    } 

ListView lv;
Button btn;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    btn = (Button)findViewById(R.id.button1);
    btn.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            new StackOverflowTask().execute();
        }
    });

    class StackOverflowTask extends AsyncTask<String, Void, JSONObject> {
        protected JSONObject doInBackground(String... urls) {
            try {
                JSONObject test = JSONfunctions.getJSONfromURL("http://emedteam-001-site1.ctempurl.com/emed/home/getdrug?letter=a");
                return test;
            } catch (Exception e) {
                return null;
            }
        }

        protected void onPostExecute(JSONObject test) {
            if(test != null)
                Toast.makeText(TestActivity.this, "Hello Stackoverflow ;)",Toast.LENGTH_SHORT).show();
    }
}