Processcommunication with Java, be informed whe process finishes.

Hello,

I have a java programm which shall open a Browser with a certain URL
AND!!!!! if this browser window is closed from a use after a while, the
java programm should be informed about this.

The following code is what I did. I am able to open a browser OS
independently.
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package com.indatex.browsercommunication;
import java.io.*;
/* Note - you must include the url type -- either "http://" or
* "file://".
*/
public class BrowserControlOSIndependent
{
     // Used to identify the windows platform.
    private String WIN_ID = "Windows";
    // The default system browser under windows.
    private String WIN_PATH = "rundll32";
    // The flag to display a url.
    private String WIN_FLAG = "url.dll,FileProtocolHandler";
    // The default browser under unix.
    private String UNIX_PATH = "netscape";
    // The flag to display a url.
    private String UNIX_FLAG = "-remote openURL";
    private Process p = null;

    public boolean hasBrowserFinished()throws Exception{
     if(p.exitValue()>0){
     return true;
     }
     p.destroy();
     return false;
    }

    public void displayURL(String url)
    {
        boolean windows = isWindowsPlatform();
        String cmd = null;
        try
        {
            if (windows)
            {
                // cmd = 'rundll32 url.dll,FileProtocolHandler
http://...'
                cmd = WIN_PATH + " " + WIN_FLAG + " " + url;
                p = Runtime.getRuntime().exec(cmd);
                try {
                    p.waitFor();
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
            else
            {
                // Under Unix, Netscape has to be running for the
"-remote"
                // command to work. So, we try sending the command and
                // check for an exit value. If the exit command is 0,
                // it worked, otherwise we need to start the browser.
                // cmd = 'netscape -remote
openURL(http://www.javaworld.com)'
                cmd = UNIX_PATH + " " + UNIX_FLAG + "(" + url + ")";
                Process p = Runtime.getRuntime().exec(cmd);
                try
                {
                    // wait for exit code -- if it's 0, command worked,
                    // otherwise we need to start the browser up.
                    int exitCode = p.waitFor();
                    if (exitCode != 0)
                    {
                        // Command failed, start up the browser
                        // cmd = 'netscape http://www.javaworld.com'
                        cmd = UNIX_PATH + " " + url;
                        p = Runtime.getRuntime().exec(cmd);
                    }
                }
                catch(InterruptedException x)
                {
                    System.err.println("Error bringing up browser,
cmd='" +
                                       cmd + "'");
                    System.err.println("Caught: " + x);
                }
            }
        }
        catch(IOException x)
        {
            // couldn't exec browser
            System.err.println("Could not invoke browser, command=" +
cmd);
            System.err.println("Caught: " + x);
        }
    }
    /**
     * Try to determine whether this application is running under
Windows
     * or some other platform by examing the "os.name" property.
     *
     * @return true if this application is running under a Windows OS
     */
    public boolean isWindowsPlatform()
    {
        String os = System.getProperty("os.name");
        if ( os != null && os.startsWith(WIN_ID))
            return true;
        else
            return false;

    }

}

-----------------------------------------------------------------------------
Thats everything fine. BUT!! if I close the Browser Window the java
programm shall be notified.
How does this work???

I thougt the easiest way is to examine the exitValue() of the process
in a lets say endles loop.
That doesnt work with process.exitValue() I always get 0, if the
browser is closed or not.

Could you help me?

Thank,
Peter