Question

iv’e been trying to learn basic java programming for the last 2 days, and I encountered an issue i can’t figgure while viewing the following code:

class DayCounter {
    public static void main(String[] arguments) {

        int yearIn = 2008;
        int monthIn = 1;
        if (arguments.length > 0)
            monthIn = Integer.parseInt(arguments[0]);
        if (arguments.length > 1)
            yearIn = Integer.parseInt(arguments[1]);
        System.out.println(monthIn + "/" + yearIn + " has "
            + countDays(monthIn, yearIn) + " days.");
    }
}

I can’t understand the line if (arguments.length > 0)
what does arguments mean? Where did the value come from?

Answer 1

Arguments is a list of Parameters that can be passed to your Java Programm at start up.

if (arguments.length > 0) checks if any arguments have been provided.

As otherwise you will be trying to access an empty array and get and index out of bounds exception.

Also there are pleanty of tutorials out there, that can help you.

Have a look at Oracle’s essentials guide, here about CMD Line Arguments.