循环结束后AsyncTask失败

Question

I want to get the content of a web directory using a php script, stored on the web server. This PHP Script I execute in an AsyncTask, here's the code:

protected ArrayList<String> doInBackground(String... urls) {
        ArrayList<String> array = new ArrayList<String>();
        try {
            URL url = new URL("http:/www.example.org/folder/script.php");
            BufferedReader br = new BufferedReader(new InputStreamReader(url.openConnection().getInputStream()));

            String line = null;

            while((line = br.readLine()) != null){
                array.add(line);

            }
            return array;

        } catch (MalformedURLException e){
            Log.e("error", e.getMessage());
            return null;
        } catch (IOException e){
            Log.e("error", e.getMessage());
            return null;
        }
    }

However, when the loop condition is fullfilled (line has the value "null") it instantly goes in the catch, but I don't even receive an exception.

I've also tried it with a for loop, same result.

String line = br.readLine();

for (; line != null ; ){
    array.add(line);
    line = br.readLine();

}
return array;

Any suggestions?