Java tutorial
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); } }