Using HttpURLConnection on UI thread (Inside Activity)

Question

using this method for getting Latitude and longitute of location entered by user working good in java but when I use this method in android , app stops automatically and exceptions/errors appears are shown in attached image

public static String[] getLatLongPositions(String address) throws Exception
{
    int responseCode = 0;
    String api = "http://maps.googleapis.com/maps/api/geocode/xml?address=" + URLEncoder.encode(address, "UTF-8") + "&sensor=true";
    URL url = new URL(api);
    HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection();
    httpConnection.connect();
    responseCode = httpConnection.getResponseCode();

    if(responseCode == 200)
    {
        DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();;
        Document document = builder.parse(httpConnection.getInputStream());
        XPathFactory xPathfactory = XPathFactory.newInstance();
        XPath xpath = xPathfactory.newXPath();
        XPathExpression expr = xpath.compile("/GeocodeResponse/status");
        String status = (String)expr.evaluate(document, XPathConstants.STRING);
        if(status.equals("OK"))
        {
            expr = xpath.compile("//geometry/location/lat");
            String latitude = (String)expr.evaluate(document, XPathConstants.STRING);
            expr = xpath.compile("//geometry/location/lng");
            String longitude = (String)expr.evaluate(document, XPathConstants.STRING);
            return new String[] {latitude, longitude};
        }
        else
        {
            throw new Exception("Error from the API - response status: "+status);
        }
    }
    return null;
}

Error: