Function overloading in ICSE Class 10, written the way the marks are given.

class Compute {
    // sum of the digits of n
    void work(int n) {
        int sum = 0;
        while (n > 0) {
            sum += n % 10;
            n /= 10;
        }
        System.out.println("Digit sum = " + sum);
    }

    // highest common factor of a and b
    void work(int a, int b) {
        while (b != 0) {
            int r = a % b;
            a = b;
            b = r;
        }
        System.out.println("HCF = " + a);
    }

    // number of vowels in s
    void work(String s) {
        int v = 0;
        s = s.toUpperCase();
        for (int i = 0; i < s.length(); i++) {
            char ch = s.charAt(i);
            if ("AEIOU".indexOf(ch) != -1)
                v++;
        }
        System.out.println("Vowels = " + v);
    }

    public static void main(String[] args) {
        Compute ob = new Compute();
        ob.work(4072);
        ob.work(84, 36);
        ob.work("Overloading");
    }
}

class Area {
    double area(double r) {
        return 3.14 * r * r;
    }

    double area(double l, double b) {
        return l * b;
    }

    double area(double a, double b, double c) {
        double s = (a + b + c) / 2;
        return Math.sqrt(s * (s - a) * (s - b) * (s - c));
    }

    public static void main(String[] args) {
        Area ob = new Area();
        System.out.println("Circle: " + ob.area(5));
        System.out.println("Rectangle: " + ob.area(7.5, 4));
        System.out.println("Triangle: " + ob.area(13, 14, 15));
    }
}

// Output
Circle: 78.5
Rectangle: 30.0
Triangle: 84.0

These are pure methods: they return a value and print nothing, so main does the printing. The int 5 is widened to double to match area(double).

// Question C. Overload void sum():
// sum(int n): 1 + 2 + ... + n
// sum(double x, int n): x/1 + x/2 + ... + x/n
class Series {
    void sum(int n) {
        int s = 0;
        for (int i = 1; i <= n; i++)
            s += i;
        System.out.println("Sum of first " + n + " numbers = " + s);
    }

    void sum(double x, int n) {
        double s = 0;
        for (int i = 1; i <= n; i++)
            s += x / i;
        System.out.println("Series sum = " + s);
    }

    public static void main(String[] args) {
        Series ob = new Series();
        ob.sum(10);
        ob.sum(6.0, 4);
    }
}

// Output
Sum of first 10 numbers = 55
Series sum = 12.5

6/1 + 6/2 + 6/3 + 6/4 = 6 + 3 + 2 + 1.5. Because x is double, x / i is real division.