Running a linux service from Java

Question

I am trying to start and stop a linux service from Java. I am using ProcessBuilder as per current accepted practices. I have constructed the following code (webService is a parameter containing the name of the service being started):

String[] commands = new String[6]; 

commands[0] = "/bin/sh";
commands[1] = "-c";
commands[2] = "sudo";
commands[3] = "service";
commands[4] = webService;
commands[5] = "start";

ProcessBuilder processBuilder = new ProcessBuilder(commands);

Process process = processBuilder.start();

int outcomeOfProcess = process.waitFor();

This effectively is calling the command /bin/sh -c sudo service webService start. Which when run from the linux terminal of the server runs fine however doesn't work from Java ProcessBuilder (outcomeOfProcess is 1 when this is run).

I have tried sudo systemctl start webservice.service as well with no avail - and I also have tried to call a bash script already located on the linux machine but this doesn't work either.

Does anyone have any ideas of how this can be fixed?

Have you set up password-less sudo? Or how do you supply the password? — Biffen, Sep 18 '15 at 12:29
try running your java process with sudo, in that way processwill run with higher access and will able to fire admin commands like `sudo` — Amey Jadiye, Sep 18 '15 at 12:35
Oh, and shouldn't that be `/bin/sh -c "sudo service webService start"`,? — Biffen, Sep 18 '15 at 12:39
Consider this library: https://commons.apache.org/proper/commons-exec/ — , Sep 18 '15 at 12:42
Is the java VM running under the same user account as when you try it in the terminal? Or is it part of a web server? — RealSkeptic, Sep 18 '15 at 12:43
I deleted my answer because the answer below addresses exactly what I was getting at. — durbnpoisn, Sep 18 '15 at 13:12

score 1 · Answer 1 · edited May 23 '17 at 12:14

Not sure ProcessBuilder can handle SO requests. For cases I need to execute host OS commands (Windows/OSX/Linux etc..), I use Runtime.exec(String):

String command = "/bin/sh -c sudo service " + webService  + " start";
Runtime.getRuntime().exec(command);

If you also want to get the output and error exit you can use Process and BufferedReader as described in this answer.

public static void main(String args[]) {
    String s;
    Process p;

    String command = "/bin/sh -c sudo service " + webService  + " start";

    try {
        // run the command
        p = Runtime.getRuntime().exec(command);
        BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream()));
        // get the result
        while ((s = br.readLine()) != null)
            System.out.println("line: " + s);
        p.waitFor();
        // get the exit code
        System.out.println ("exit: " + p.exitValue());
        p.destroy();
    } catch (Exception e) {}
}

NOTE: not a Linux expert, so I can't tell 100% your command line is correct, but yes you can execute it in this way.

score 0 · Answer 2 · answered Sep 18 '15 at 14:09

0

The problem was the sudoers file which prevented the code executing without a tty changing this file slightly meant that it would accept code. Nightmare debugging this as it has taken all day! thanks for all the input!

answered Sep 18 '15 at 14:09

joelc

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Running a linux service from Java

2 Answers2