How to use Java for ShutDown Computer From using Code

//******************Start**************************

import java.io.*;

/**
 *
 * @author HP
 */
public class Shut_Down_Computer {
public static void main(String args[]) throws IOException
    {
        Runtime runtime = Runtime.getRuntime();
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));

        System.out.print("Enter No. of Seconds after which You want your Computer to Shutdown :");
        long a=Long.parseLong(br.readLine());

        Process proc = runtime.exec("shutdown -s -t " +a);

        System.exit(0);
    }
}

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