Android : How to use the java-json library in Android

I have an AsyncTask that fetches XML data from the internet. I want to convert it into JSON and am using the java-json library. But the app crashes on me. This is the AsyncTask

private class GetBlogPostsTask extends AsyncTask<Object, Void, JSONObject> {

    @Override
    protected JSONObject doInBackground(Object... arg0) {
        int responseCode = -1;
        JSONObject jsonResponse = null;
        try {
            URL blogFeedUrl = new URL("some url");
            HttpURLConnection connection = (HttpURLConnection) blogFeedUrl.openConnection();
            connection.connect();
            responseCode = connection.getResponseCode();
            if (responseCode == HttpURLConnection.HTTP_OK) {
                InputStream inputStream = connection.getInputStream();
                ByteArrayOutputStream out = new ByteArrayOutputStream();
                byte[] buffer = new byte[1024];
                for (int count; (count = inputStream.read(buffer)) != -1; ) {
                out.write(buffer, 0, count);
                }
                byte[] response = out.toByteArray();
                String responseData = new String(response, "UTF-8");
                Log.d("TAG", responseData);
                try {
                    jsonResponse = XML.toJSONObject(responseData);
                } catch (JSONException e) {
                    Log.e("JSON exception", e.getMessage());
                    e.printStackTrace();
                } 

            } else {
                Log.i(TAG, "Unsuccessful HTTP Response Code: "
                        + responseCode);
            }
        } catch (MalformedURLException e) {
            logException(e);
        } catch (IOException e) {
            logException(e);
        } catch (Exception e) {
            logException(e);
        }

        return jsonResponse;
    }

I am successfully retrieving the XML data because I can see it in the Logcat. I think my problem is that I'm not using the library properly. The Logcat shows the following error messages when the app crashes

09-08 04:58:42.262: E/AndroidRuntime(1112): FATAL EXCEPTION: AsyncTask #1
09-08 04:58:42.262: E/AndroidRuntime(1112): Process: com.example.xmltojsontest, PID: 1112
09-08 04:58:42.262: E/AndroidRuntime(1112): java.lang.RuntimeException: An error occured while executing doInBackground()
09-08 04:58:42.262: E/AndroidRuntime(1112):     at android.os.AsyncTask$3.done(AsyncTask.java:300)
09-08 04:58:42.262: E/AndroidRuntime(1112):     at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
09-08 04:58:42.262: E/AndroidRuntime(1112):     at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
09-08 04:58:42.262: E/AndroidRuntime(1112):     at java.util.concurrent.FutureTask.run(FutureTask.java:242)
09-08 04:58:42.262: E/AndroidRuntime(1112):     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
09-08 04:58:42.262: E/AndroidRuntime(1112):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
09-08 04:58:42.262: E/AndroidRuntime(1112):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
09-08 04:58:42.262: E/AndroidRuntime(1112):     at java.lang.Thread.run(Thread.java:841)
09-08 04:58:42.262: E/AndroidRuntime(1112): Caused by: java.lang.NoSuchMethodError: org.json.XMLTokener.end
09-08 04:58:42.262: E/AndroidRuntime(1112):     at org.json.XMLTokener.nextCDATA(XMLTokener.java:69)
09-08 04:58:42.262: E/AndroidRuntime(1112):     at org.json.XML.parse(XML.java:165)
09-08 04:58:42.262: E/AndroidRuntime(1112):     at org.json.XML.parse(XML.java:272)
09-08 04:58:42.262: E/AndroidRuntime(1112):     at org.json.XML.parse(XML.java:272)
09-08 04:58:42.262: E/AndroidRuntime(1112):     at org.json.XML.parse(XML.java:272)
09-08 04:58:42.262: E/AndroidRuntime(1112):     at org.json.XML.toJSONObject(XML.java:369)
09-08 04:58:42.262: E/AndroidRuntime(1112):     at com.example.xmltojsontest.MainActivity$GetBlogPostsTask.doInBackground(MainActivity.java:168)
09-08 04:58:42.262: E/AndroidRuntime(1112):     at com.example.xmltojsontest.MainActivity$GetBlogPostsTask.doInBackground(MainActivity.java:1)
09-08 04:58:42.262: E/AndroidRuntime(1112):     at android.os.AsyncTask$2.call(AsyncTask.java:288)
09-08 04:58:42.262: E/AndroidRuntime(1112):     at java.util.concurrent.FutureTask.run(FutureTask.java:237)
09-08 04:58:42.262: E/AndroidRuntime(1112):     ... 4 more

Thank you in advance for any help.