JAVA 8 Lambda Expression

Following example explain how Lambda Expression can be implemented in JAVA 8.

    interface MathOperation {

        int execute(int a, int b);

    }

    public int calculate(int a, int b, MathOperation op) {

        return op.execute(a, b);

    }

    public static void main(String[] args) {

        Lamda lamda = new Lamda();

        MathOperation addition = (a, b) -> (a + b);

        MathOperation substract = (a, b) -> (a - b);

        System.out.println(lamda.calculate(4, 5, addition));

        System.out.println(lamda.calculate(4, 5, substract));

    }