Runtime.exec and locked window

Question

So I'm working in a Swing application guaranteed to run only on Windows systems using Java 1.6 u 7. The users want a help button to launch a local web browser and point to the company's web site.
After reading online and finding that getDesktop.browse() sometimes crashes in that version of Java, I use Runtime.exec("rundll ...") to kick off the local browser with the appropriate web address.
The browser comes up appropriately, but the original Swing application's mouse pointer converts to an hourglass; I can click on the original window and get results but I can't open a new window.
So I create a short thread implementing the Runnable interface and put the Runtime.exec call in that thread; I assume the problem is that the process is interfering with the GUI thread, and putting the Runtime.exec call in a separate thread will clear the problem up. It doesn't work; I still have the hourglass.
I read online that some processes require that their input and error streams be consumed, or they may block; That shouldn't be a problem with internet explorer, but I add two threads to consume those streams; still no change.
I also tried getDesktop().browse() anyway, and in a separate thread, and had the same problem.
Does anyone have any suggestions?
Respectfully,
Brian P.

Answer 1

Okay.
First, let's look at the basic client.
As you can see, when asked to show a window,
it puts it in a separate thread for rendering:
public class Client     
// Show one example method
     private void showNewWindow(Window window)
          ourLogger.info("New request to display window: " + window.getClass().getName());
          if (window instanceof ClientWindow)
               try
                    ((ClientWindow) window).bindFrames();
                    ((ClientWindow) window).setClient(this);
                    if (window instanceof ClientJDialog)
                         window = new ClientJDialog((ClientJDialog) window);
                    else
                         correctSize(window);
                    showCenter(window);
                    synchronized(myWindows)
                         myWindows.add(window);
                    counter = 0;
                    thread.hide();
               catch (Exception re)
                    ourLogger.error("Client error while trying to show window", re);
                    ((ClientWindow) window).unbindFrames(false);
          else
               throw new Error(window.getClass().getName() + " is NOT an instance of ClientWindow");
// Snip some more
At this same level on this class, I had originally put a showHelp() procedure with a single
command thus:
     public void showHelp()
          Desktop.getDesktop().browse(java.net.URI.create(<help web site>));
Simple, eh? But that gave me the hourglass as discussed. So I pushed it into a new thread.
It eventually mutated thus:
     public void showHelp()
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
          //windows only
          Runtime rt = Runtime.getRuntime();
          Process p = rt.exec("rundll32 url.dll,FileProtocolHandler " + "<help URL>");
          StreamGobbler s1 = new StreamGobbler ("stdin", p.getInputStream ());
          StreamGobbler s2 = new StreamGobbler ("stderr", p.getErrorStream ());
          s1.start ();
          s2.start ();
          try {
          p.waitFor();
          } catch (java.lang.InterruptedException e) {}
So as you can see, I ditched Desktop from Runtime and added a pair of stream consumers
to ensure I wasn't having the stream problem our second poster discussed. Still no joy.
I eventually replaced the url call with an attempt to invoke a simple batch file which
did nothing, and I still had the same problem. I still have an hour glass, even when
the process has been pushed into a new thread as you can see.
Respectfully,
Brian P.
Edited by: pendell on Apr 16, 2010 3:14 PM