Check url existence without opening browser, in java

I want to check the existence of a url and i tried with the 开发者_开发百科following code in java,

public boolean exists(String URLName) {
    try {
         if (!URLName.toUpperCase().contains("HTTP")) 
             URLName="http://"+URLName;
             URL url = new URL(URLName);
             System.setProperty("java.net.useSystemProxies", "true");
             HttpURLConnection urlConn = (HttpURLConnection)  url.openConnection();
                 urlConn.setConnectTimeout(9000);
         urlConn.setReadTimeout(9000);            
          urlConn.connect();                    
                         if(HttpURLConnection.HTTP_OK == urlConn.getResponseCode())
             return true;
else
             return false;
  }
 catch (SocketTimeoutException e){
        return false;
   }

 catch (Exception e) {
       e.printStackTrace();
       return false;
   }
}

The above code is working fine in windows but when the code is run through server (linux) i am getting the following error message,

GConf Error: Failed to contact configuration server; some possible
causes are that you need to enable TCP/IP networking for ORBit, or
you have stale NFS locks due to a system crash. See
http://projects.gnome.org/gconf/ for information. (Details - 1:
Not running within active session)
GConf Error: Failed to contact configuration server; some possible
causes are that you need to enable TCP/IP networking for ORBit, or
you have stale NFS locks due to a system crash. See
http://projects.gnome.org/gconf/ for information. (Details - 1:
Not running within active session)
java.net.UnknownHostException: www.ep.gov
at
java.net.PlainSocketImpl.connect(PlainSocketImpl.j ava:177)
at
java.net.SocksSocketImpl.connect(SocksSocketImpl.j ava:366)
at java.net.Socket.connect(Socket.java:525)
at sun.net.NetworkClient.doConnect(NetworkClient.java :158)
at
sun.net.http://www.http.HttpClient.openServe...lient.java:394)
at
sun.net.http://www.http.HttpClient.openServe...lient.java:529)
at sun.net.www.http.HttpClient.<init>(HttpClient.java :233)
at sun.net.www.http.HttpClient.New(HttpClient.java:306)
at sun.net.www.http.HttpClient.New(HttpClient.java:323)
at
sun.net.http://www.protocol.http.HttpURLConn...ction.java:860)
at
sun.net.http://www.protocol.http.HttpURLConn...ction.java:801)
at
sun.net.http://www.protocol.http.HttpURLConn...ction.java:726)

I got the below message from server admin

It is working, while it was run in X session (GUI Mode).
But it is not working in non-GUI mode. Please try to change the coding to make use of non-GUI mode." It seems the above code is making use of GUI mode. 

I need an alternate code to check url existence without using GUI.

Regards Linda

UnknownHostException means that the request is not reaching to its destination. There could be many reason that the linux server is unreachable to the desired URL www.ep.gov.

Please make sure that the server can reach the URL www.ep.gov.

I think your problem is with this line:

System.setProperty("java.net.useSystemProxies", "true");

It seems this causes the system to try and find the HTTP proxy configuration for the web browser, and ends up running into some problems with the Gnome configuration.

Do you actually need to use a HTTP proxy? If not, simply remove that line. If you do, read this page to learn how to configure proxies.