How do I Remotely shutdown another computer using java

Question

I've connected two machines in virtual box. I know that the machines are connected because I was able to detect the os of the target windows machine

Aim: Use one machine to shutdown the target windows machine using a java program which accepts a user input: ip

Problem: When the program executes it skips

runtime.exec("shutdown /m /t0 \\" +ip);

Therefore it does not shutdown the targeted computer.

Question: Why is this happening and how can I solve the issue?

import java.io.IOException;
import java.util.Scanner;
public class RemoteShutdown
{


    /*Shutdown user's computer*/
    public void shutdown(String ip )
    {
        Runtime runtime = Runtime.getRuntime();
      
            try
            {
                runtime.exec("shutdown /s  /m \\" +ip);
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }

       
    }

    public static void main(String[] args) throws Exception
    {
        Scanner scanner = new Scanner(System.in);
        RemoteShutdown shutDown = new RemoteShutdown();

        System.out.print("Enter computer IP: ");
        String IP = scanner.next().trim();

        shutDown.shutdown(IP);

    }

}

Answer 1

1. relative paths are usually a bad idea in runtime.exec . You have little control of the path; a better option would be to fetch the windows home dir via System.getenv and craft your own route to C:\Windows\System32, or wherever 'shutdown.exe' lives.

2. Usually this needs admin access, so what you want may be impossible, or may requiring launching java with admin rights.

3. Generally, don't use exec, but use ProcessBuilder . Trying to navigate how args are split is rather confusing with just the basic exec .

4. In java, \ in a string is an escape single. "\\" is a string containing only one backslash , but you want to send 2 backslashes to windows here, so, in java, you'd write "\\\\" + ip .

5. exec returns a Process object, and you tell it to combine output and error, and then you can fetch the output and error streams. This helps a lot: In this case, no doubt shutdown.exe is telling you that the specification of the other computer is erroneous (due to, effectively, a missing backslash), but you never read this data. A web search for 'ProcessBuilder java example read output' will probably get you multiple in-depth posts.