HttpURLConnection locks up on connect()

public static boolean isReachableURL(URL url)
    throws MalformedURLException, IOException, Exception {
        System.out.println("Testing to see if URL connects");
        HttpURLConnection conn =
(HttpURLConnection)url.openConnection();
        System.out.println("Created HttpURLConnection object");
        conn.connect();
        System.out.println("connecting..");
        boolean isConnected = (conn.getContentLength() > 0);
        System.out.println("disconnecting..");
        conn.disconnect();
        System.out.println("disconnected");
        return isConnected;
    }

I am trying to simply determine if a URL provided is a "reachable URL",
if so, return true, else, return false.

On most URLs I have no problem distinguishing reachable from
unreachable, but if you try something like this:

http://blah.com

It will lock up tight as a drum and I have to break into Windows Task
Manager to stop the process as it runs as an infinite loop at this
point.

So how can I reliably determine if a URL is reachable or unreachable?

Thanx
Phil