CODEWITHSUNDEEP
javajschnohup
peter
peter

Reputation: 631

jsch & nohup - program doesn't start

I want to start my program in the background using jsch and 'nohup with &' command. This is my code:

    String command = "sudo nohup -jar [path to my jar] &";
    try{
        java.util.Properties config = new java.util.Properties();
        config.put("StrictHostKeyChecking", "no");
        JSch jsch = new JSch();
        Session session = jsch.getSession(user, host, 22);
        session.setPassword(password);
        session.setConfig(config);
        session.connect();
        System.out.println("Connected");

        Channel channel = session.openChannel("exec");
        ((ChannelExec)channel).setPty(true);
        ((ChannelExec)channel).setCommand(command);
        channel.setInputStream(null);
        ((ChannelExec)channel).setErrStream(System.err);

        InputStream in = channel.getInputStream();
        channel.connect(); 
        byte[] tmp = new byte[1024];
        while (true) {
            while (in.available() > 0) {
                int i = in.read(tmp, 0, 1024);
                if (i < 0) {
                    break;
                }
                System.out.print(new String(tmp, 0, i));
            }

            if (channel.isClosed()) {
                System.out.println("exit-status: " + channel.getExitStatus());
                break;
            }

            try {
                Thread.sleep(1000);
            } catch (Exception ee) {
            }
        }
        channel.disconnect();
        session.disconnect();
        System.out.println("DONE");
    } catch(Exception e) {
        e.printStackTrace();
    }

As the output I get:

Connected
exit-status: 0
DONE

but the program is not started. Without '&' it works, but with it doesn't. The same situation is when I put nohup command into .sh script and then run it. Any ideas how to solve this problem?

Thanks in advance!

Upvotes: 1

Views: 2591

Answers (2)

codefiler
codefiler

Reputation: 1

Replace this line:

String command = "sudo nohup -jar [path to my jar] &";

with this:

String command = "sudo nohup -jar [path to my jar]>out.log 2>&1 &";

Upvotes: 0

jmsu
jmsu

Reputation: 2053

3 years later...

I've recently had the same problem. I solved it by using:

((ChannelExec)channel).setPty(false);

and by redirecting the output stream. It seems to me it depends on the program being executed. I had a different script that just slept and printed date to a file and it didn't need any redirect. Also it was independent of JSch. Using the command line ssh the problem also existed.

The command I actually wanted to execute needed its output stream redirected away from stdout. If redirecting the stdout alone does not work redirecting the error stream and closing the input stream with <&- might help.

Upvotes: 0

Related Questions