Stuck On Runtime.exec() with cmd.exe

Question

I've done my best to look through the forums and implement what's been said but I'm getting a problem where my whole Java program freezes when the exec() is executed. Can anyone tell me what I'm missing or have misunderstood ?
        try
            Process runSmodels = Runtime.getRuntime().exec("C:\\Windows\\System32\\cmd.exe lparse predict.pl | smodels 0");
            String smodelsOutput = new String();
            BufferedReader smodelsReader = new BufferedReader(new InputStreamReader(runSmodels.getInputStream()));
            String outputLine = smodelsReader.readLine();
            while(outputLine != null)
                smodelsOutput += outputLine;
                outputLine = smodelsReader.readLine();
            smodelsReader.close();
            System.out.println(smodelsOutput);
        catch(IOException exc)
            JOptionPane.showMessageDialog(rootPane, "Could not access Smodels.", "System Call Error", JOptionPane.ERROR_MESSAGE);
        }

Answer 1

DarioAtUOW wrote:
Pitfall 1 : Calling .exitValue(). My code doesn't do that.
Pitfall 2 :Not enptying relevant streams. I do empty the input stream.
Pitfall 3 : Assuming a command is an executable program. I don't do that, cmd.exe is in my command string explicitly.
Pitfall 4 : As above in Pitfall 3.
So, why accuse me of not reading the article ? You probably have many years of experience at Java, unlike me, who is just starting out with it at university.Pitfall 2 : Even though you are processing stdout you are not processing stderr! Always always always process both. This may or may not be the cause of your problem but by copying the process stderr to your System.err you may see why your process is stuck.
Even Clippy, the Microsoft Office Assistant, could answer questions better than you have attempted to do.Ouch, I'm cut to the bone on your razor sharp wit. Phuck you.