Why is website crawling taking forever?

public class Parser {

    public static void main(String[] args) {
        Parser p = new Parser();
        p.matchString();
    }

    parserObject courseObject = new parserObject();
    ArrayList<parserObject> courseObjects = new ArrayList<parserObject>();
    ArrayList<String> courseNames = new ArrayList<String>();
    String theWebPage = " ";

    {
        try {
            URL theUrl = new URL("http://ocw.mit.edu/courses/");
            BufferedReader reader =
                new BufferedReader(new InputStreamReader(theUrl.openStream()));
            String str = null;

            while((str = reader.readLine()) != null) {
                theWebPage = theWebPage + " " + str;
            }
            reader.close();

        } catch (MalformedURLException e) {
            // do nothing
        } catch (IOException e) {
            // do nothing
        }
    }

    public void matchString() {
        // this is my regex that I am using to compare strings on input page
        String matchRegex = "#\\w+(-\\w+)+";

        Pattern p = Pattern.compile(matchRegex);
        Matcher m = p.matcher(theWebPage);

        int i = 0;
        while (!m.hitEnd()) {
            try {
                System.out.println(m.group());
                courseNames.add(i, m.group());
                i++;
            } catch (IllegalStateException e) {
                // do nothing
            }
        }
    }
}

What I am trying to achieve with the above code is to get the list of departments on the MIT OpencourseWare website. I am using a regular expression that matches the pattern of the department names as in the page source. And I am using a Pattern object and a Matcher object and trying to find() and print these department names that match the regular expression. But the code is taking forever to run and I don't think reading in a webpage using bufferedReader takes that long. So I think I am either doing something horribly wrong or parsing websites takes a ridiculously long time. so I would appreciate any input on how to improve performance or correct a mistake in my code if any. I apologize for the badly written code.