Runtime.exec lifecycle

Question

I am trying to execute a client using the following code below. It works fine when i run as stand alone java program. I am familiar with the javaworld article "When Runtime.exec() won't" ...
Process p = Runtime.getRuntime().exec("\"c:\a b\\client.exe\" "\"some param\"""); //   "c:\a b\client.exe" "some param"
            InputStream in = p.getInputStream();
            InputStream err = p.getErrorStream();
            BufferedReader br = new BufferedReader(new InputStreamReader(in));
            String line = null;
            while ((line = br.readLine()) != null) {           }
            in.close();            br.close();
            br = new BufferedReader(new InputStreamReader(err));
            while ((line = br.readLine()) != null) {            }
            p.destroy();But when I incorporate it to a web application using jrun it crashes in windows, shows the debug dialog. I don't get any exceptions.
Any clues?

Answer 1

As has already been pointed out, you do need to follow the recommendations in the 'traps' article but you seem to have ignored two of them.
First, you don't read stdout and stderr in separate threads. You can use the control thread to read one of them and a separate thread to read the other. Even better, if your really don't care about the content of stdout and stderr then use ProcessBuilder and redirect stderr to stdout and read stdout as you currently do.
Second, you don't wait for the process to terminate. Even worse, you destroy() it! Don't do this. This is possibly why the process crashes! Always wait for the process to complete and always check the exit code.
Now not part of the 'traps' article but a bit of advice - when debugging a Runtime.exec() problem or a ProcessBuilder problem ALWAYS write the stdout and stderr out somewhere. It is a very very very useful bit of diagnostic information.