org.json.simple.JSONObject cannot be cast to org.json.JSONObject

Change your code as:

  org.json.simple.JSONObject jsonObject = null;
  JSONParser parser=new JSONParser(); // this needs the "json-simple" library

  try 
  {
        Object obj = parser.parse(responseBody);
        jsonObject=(org.json.simple.JSONObject)obj;
  }
  catch(Exception ex)
  {
        Log.v("TEST","Exception1: " + ex.getMessage());
  }

or if you are using only org.json.simple library for parsing json string then just import org.json.simple.* instead of org.json.JSONObject

If you want to use an org.json.JSONObject you can do it by replacing this:

JSONObject jsonObject = null;
JSONParser parser=new JSONParser(); // this needs the "json-simple" library

try 
{
    Object obj = parser.parse(responseBody);
    jsonObject=(JSONObject)obj;
}
catch(Exception ex)
{
    Log.v("TEST","Exception1: " + ex.getMessage());
}

with:

JSONObject jsonObject = null;
JSONParser parser=new JSONParser(); // this needs the "json-simple" library

try 
{
    String obj = parser.parse(responseBody).toString(); //converting Object to String
    jsonObject = new JSONObject(obj); // org.json.JSONObject constructor accepts String as an argument
}
catch(Exception ex)
{
    Log.v("TEST","Exception1: " + ex.getMessage());
}