import java.io.*;
    import java.util.ArrayList;
    
    public class ExecDemo {
        static public String[] runCommand(String cmd)
            throws IOException {
    
            // set up list to capture command output lines
    
            ArrayList list = new ArrayList();
    
            // start command running
   
            Process proc = Runtime.getRuntime().exec(cmd);
    
            // get command's output stream and
            // put a buffered reader input stream on it
    
            InputStream istr = proc.getInputStream();
            BufferedReader br =
                new BufferedReader(new InputStreamReader(istr));
    
            // read output lines from command
    
            String str;
            while ((str = br.readLine()) != null)
                list.add(str);
    
            // wait for command to terminate
    
            try {
                proc.waitFor();
            }
            catch (InterruptedException e) {
                System.err.println("process was interrupted");
            }
    
            // check its exit value
    
            if (proc.exitValue() != 0)
                System.err.println("exit value was non-zero");
    
            // close stream
    
            br.close();
    
            // return list of strings to caller
    
            return (String[])list.toArray(new String[0]);
        }
    
        public static void main(String args[]) throws IOException {
            try {
    
                // run a command
    
                String outlist[] = runCommand("test");
    
                // display its output
    
                for (int i = 0; i < outlist.length; i++)
                    System.out.println(outlist[i]);
            }
            catch (IOException e) {
                System.err.println(e);
            }
        }
    }