Server is up/down???

Question

Dear All,
     I am trying to get authentication from my server, by using the below function...Here is a doubt...Once if my server is in "DOWN" state, i am getting the errors fired in my command prompt...how can i avoid this???.....i mean, i want to avoid the process of authentication, if the server is "DOWN"....how to find out whether a server is running in that url or not????
public String authenticateMe(String username, String password)
String setcookie="";
String cookie="";
try
URL theurl = new URL("http://192.168.10.55:8001/names.nsf?login&username=" + username + "&password=" + password);
HttpURLConnection.setFollowRedirects(false);
HttpURLConnection hurl = (HttpURLConnection)theurl.openConnection();
hurl.connect();
setcookie = hurl.getHeaderField ("set-cookie");
if(setcookie!=null)
int index=setcookie.indexOf(";");
cookie=(setcookie.substring(0,index)).trim();
hurl.disconnect();
hurl=null;
catch(Exception exp)
{exp.printStackTrace();}
return cookie;
bye,
Sakthivel S.

Answer 1

I haven't used the Timer class much myself. Would suggest you look at the tutorial at: http://java.sun.com/docs/books/tutorial/uiswing/misc/timer.html
and at the API documentation. Together they should have all the info. you need.
Then just experiment until you get it to work. If you run into any problems post again to ask someone else.
To start you off, I was thinking of something along the following lines (untested, just typed straight in):
private javax.swing.Timer timer;
private final int MILLISECONDS_DELAY = 15 * 60 * 1000; // 15 minutes
private void login()
    // code to login here
    // successful login
    if (timer == null) // if first time
         // create timer passing anonymous ActionListener to
         // handle event fired after delay
         timer = new Timer(MILLISECONDS_DELAY, new ActionListener()
             public void actionPerformed(ActionEvent ev)
                 login();
         timer.setRepeats(true); // keeps repeating itself
         timer.start(); // start it off
// assumes client has logged in to server already
private void request()
    // send request to server
    timer.restart(); // reset timer to zero
}