Java Code Example: check leap year in if else statement

A normal year has 365 days. Every four years, however, there is a leap year with 366 days. This is because the earth does not need exactly 365 days to travel once around the sun, but about a quarter day more. So a year has one day more every 4 years.

So that the calculation is correct, there is no leap year every 100 years. Nevertheless, every four hundred years a leap year takes place. This concerns the years 2000, 2400 etc.

Code Explanation

This Java program is checking if a given year is a leap year or not.

The program has a static method isLeapYear which takes an integer argument year and returns a boolean value. The method first checks if the year is not divisible by 4, it returns false, because a leap year must be divisible by 4. If it is divisible by 4, it checks if it is divisible by 400, if it is, it returns true, because a year that is divisible by 400 is always a leap year. If it’s not divisible by 400, it checks if it’s divisible by 100, if it is, it returns false, because a year that is divisible by 100 but not divisible by 400 is not a leap year. If it’s not divisible by 100, it returns true because it is a leap year.

In the main method, an integer variable year is declared and assigned a value of 2020. The program then calls the isLeapYear method and passes the value of year as an argument. The returned value of isLeapYear is then used in an if-else statement to determine if the year is a leap year or not. If it is a leap year, a message is printed saying the year is a leap year, and if it’s not, a message is printed saying the year is not a leap year.

class CheckLeapYearExample {
    public static boolean isLeapYear(int year) {
        if (year % 4 != 0) {
            return false;
        } else if (year % 400 == 0) {
            return true;
        } else if (year % 100 == 0) {
            return false;
        } else {
            return true;
        }
    }

    public static void main(String[] args) {
        int year = 2020;

        if (isLeapYear(year)) {
            System.out.println(year + " is a leap year");
        } else {
            System.out.println(year + " is not a leap year");
        }
    }
}

Output

2020 is a leap year