How to detect the presence of URL in a string

import java.net.URL;
import java.net.MalformedURLException;

// Replaces URLs with html hrefs codes
public class URLInString {
    public static void main(String[] args) {
        String s = args[0];
        // separete input by spaces ( URLs don't have spaces )
        String [] parts = s.split("\s");

        // Attempt to convert each item into an URL.
        for( String item : parts ) try {
            URL url = new URL(item);
            // If possible then replace with anchor...
            System.out.print("<a href="" + url + "">"+ url + "</a> " );
        } catch (MalformedURLException e) {
            // If there was an URL that was not it!...
            System.out.print( item + " " );
        }

        System.out.println();
    }
}

"Please go to http://stackoverflow.com and then mailto:[email protected] to download a file from    ftp://user:pass@someserver/someFile.txt"

Please go to <a href="http://stackoverflow.com">http://stackoverflow.com</a> and then <a href="mailto:[email protected]">mailto:[email protected]</a> to download a file from    <a href="ftp://user:pass@someserver/someFile.txt">ftp://user:pass@someserver/someFile.txt</a>

url.getProtocol();

(?bhttp://[-A-Za-z0-9+&@#/%?=~_()|!:,.;]*[-A-Za-z0-9+&@#/%=~_()|]

if (s.StartsWith("(") && s.EndsWith(")"))
{
    return s.Substring(1, s.Length - 2);
}

String originalString = "Please go to http://www.stackoverflow.com";
String newString = originalString.replaceAll("http://.+?(com|net|org)/{0,1}", "<a href="$0">$0</a>");

String msg = "Please go to http://stackoverflow.com";
String withURL = msg.replaceAll("(?:https?|ftps?)://[\w/%.-]+", "<a href='$0'>$0</a>");
System.out.println(withURL);