Calling external program in java with timeout

Question

I am facing an issue calling an external program from java with timeout. I got the below code. This program tries to open notepad.exe through java and terminates after 5 seconds. The problem I am facing is that although its terminating the notepad, the java process still remains active (eclipse does not terminate). Experts please help!

public class ExecTest {

public static void main(String[] args) {
    System.out.println("STARTING");
    new ExecTest().callNotepad();
    System.out.println("ENDING");
}

public ExecTest() {
}

private void callNotepad() {
    ProcessBuilder pb = new ProcessBuilder("notepad.exe");
    pb.redirectErrorStream(true);
    try {
        Timer t = new Timer();
        pb.redirectErrorStream(true);
        Process p = pb.start();
        TimerTask killer = new TimeoutProcessKiller(p);
        t.schedule(killer, 5000);
        try {
            InputStream is = p.getInputStream();
            InputStreamReader isr = new InputStreamReader(is);
            BufferedReader br = new BufferedReader(isr);
            String line = "";
            while ((line = br.readLine()) != null) {
                System.out.println(line + "\n");
            }
            p.waitFor();
            System.out.println("HERE!");
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } finally {
            System.out.println("Cancelling timer");
            killer.cancel();
            System.out.println("Cancelled timer");
        }

    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}
}

class TimeoutProcessKiller extends TimerTask {
private Process p;
public TimeoutProcessKiller(Process p) {
    this.p = p;
}

@Override
public void run() {
    System.out.println("Destroying thread p=" + p);
    p.destroy();
    System.out.println("Destroyed thread p=" + p);
}

}

Gren · Accepted Answer · 2015-01-28 13:33:30Z

2

You have cancelled the TimerTask killer instead of the Timer t.
Just exchange killer.cancel(); with t.cancel()

answered Jan 28, 2015 at 13:33

Gren

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