String[] cmd = new String[4];
cmd[0] = "cmd.exe";
cmd[1] = "/C";
cmd[2] = "start";
cmd[3] = "http://www.javaprogrammingforums.com";
Process p = Runtime.getRuntime().exec(cmd);

public static void openBrowser(String URL) {
            String browserPath = "C:/Program Files/Mozilla Firefox/firefox.exe";
            String url = URL;
                try {
                        String[] b = {browserPath, url};
                        Runtime.getRuntime().exec(b);
                     }
                    catch (Exception exc) {
                exc.printStackTrace();
                    }
    }

package com.centerkey.utils;

import java.lang.reflect.Method;
import javax.swing.JOptionPane;
import java.util.Arrays;

/**
 * <b>Bare Bones Browser Launch for Java</b><br>
 * Utility class to open a web page from a Swing application
 * in the user's default browser.<br>
 * Supports: Mac OS X, GNU/Linux, Unix, Windows XP/Vista<br>
 * Example Usage:<code><br> &nbsp; &nbsp;
 *    String url = "http://www.google.com/";<br> &nbsp; &nbsp;
 *    BareBonesBrowserLaunch.openURL(url);<br></code>
 * Latest Version: <a href="http://www.centerkey.com/java/browser/">www.centerkey.com/java/browser</a><br>
 * Author: Dem Pilafian<br>
 * Public Domain Software -- Free to Use as You Like
 * @version 2.0, May 26, 2009
 */
public class BareBonesBrowserLaunch {

   static final String[] browsers = { "firefox", "opera", "konqueror", "epiphany",
      "seamonkey", "galeon", "kazehakase", "mozilla", "netscape" };

   /**
    * Opens the specified web page in a web browser
    * @param url A web address (URL) of a web page (ex: "http://www.google.com/")
    */
   public static void openURL(String url) {
      String osName = System.getProperty("os.name");
      try {
         if (osName.startsWith("Mac OS")) {
            Class<?> fileMgr = Class.forName("com.apple.eio.FileManager");
            Method openURL = fileMgr.getDeclaredMethod("openURL",
               new Class[] {String.class});
            openURL.invoke(null, new Object[] {url});
            }
         else if (osName.startsWith("Windows"))
            Runtime.getRuntime().exec("rundll32 url.dll,FileProtocolHandler " + url);
         else { //assume Unix or Linux
            boolean found = false;
            for (String browser : browsers)
               if (!found) {
                  found = Runtime.getRuntime().exec(
                     new String[] {"which", browser}).waitFor() == 0;
                  if (found)
                     Runtime.getRuntime().exec(new String[] {browser, url});
                  }
            if (!found)
               throw new Exception(Arrays.toString(browsers));
            }
         }
      catch (Exception e) {
         JOptionPane.showMessageDialog(null,
            "Error attempting to launch web browser\n" + e.toString());
         }
      }

   }

if (Desktop.isDesktopSupported())
            Desktop.getDesktop().browse(new URI("www.google.com"));