Use of argv to get an integer value from command line in Java

/*from   w w  w.ja va2s .  co m*/
public class Main {
  public static void main(String[] argv) {
    int number = 0;

    System.out.println("The number of words in argv is " + argv.length);

    if (argv.length == 0) {
      number = 1234;
    } else if (argv.length == 1) {
      try {
        number = Integer.parseInt(argv[0]);
      } catch(NumberFormatException e) {
        System.err.println("Number " + argv[0] + " invalid (" + e.getMessage() + ").");
        System.exit(1);
      }
    } else {
      System.err.println("usage: UseArgv number");
      System.exit(1);
    }

    System.out.println("OK, number is " + number);
  }
}